Holidaymakers refusing to leave a popular part of Victoria face being trapped by fires after authorities shut a highway and issued ten emergency warnings.

About 30,000 tourists as well as 45,000 locals were told to leave the East Gippsland region on Sunday in what would be one of the biggest mass evacuations in Australia's history.

An emergency warning, the highest possible alert, was issued for a blaze west of Goongerah, in East Gippsland, on Monday afternoon and an evacuation order remains in place.

Another emergency warning also was issued on Monday afternoon for a fire burning 13km from Walwa in the northeast, near the NSW border.

Emergency warnings have also been issued in East Gippsland for the W Tree fire, Ramrod Creek, Bullumwaal, Clifton Creek, Deptford, Mount Taylor, Waterholes and Fairhope.

The highest alert has also been issued for Suggan Buggan, Buchan, Buchan South and Sunny Point. Suggan Buggan is a border town, also threatened by out-of-control blazes in NSW.

Similar alerts were already in place on Monday for the Ensay-Barmouth Spur fire, and the Wingan River fire. The Ensay-Barmouth Spur fire had been two fires but joined overnight and has burnt about 100,000 hectares.

'You are in danger and need to act immediately to survive. The safest option is to take shelter indoors immediately. It is too late to leave,' some of the emergency warnings said.

The Princes Highway between Cann River and Genoa was shut at 1pm amid the increased fire activity in the area and residents were told it's too late to leave.

'It is quite an extreme day for us, really the first really bad day that we've had on this group of fires since they started on the 21st of November,' East Gippsland fires incident controller Ben Rankin told reporters at Bairnsdale.

'[It's] comparable almost to Black Saturday in some ways, if the forecast does eventuate as given to us. It is inevitable there will be some significant run of fire today.'

Despite the plea for 30,000 holidaymakers in Lakes Entrance to leave on Sunday, the town is unlikely to be impacted by the fires and is a good place to take refuge, he added.

'We didn't want people moving around the road today because of the high risk of fire movement and impact to the roadways would see impact on visitors,' Mr Rankin said.

Temperatures have soared into the 40s across Victoria on Monday, with a total fire ban in place across the state and extreme fire danger ratings in most regions.

The weather bureau expects strong and gusty winds throughout Monday, as well as thunderstorms that will give way to much cooler air and rain.

The temperature has reached 42C in Bairnsdale, ahead of a top of 43C, before a cool change hits West Gippsland on Monday night and East Gippsland on Tuesday morning.

Bureau of Meteorology senior forecaster Kevin Parkyn said a wind change could be more dangerous for the conditions, the ABC reported.

'It's a very serious, life-threatening situation, make no mistake about it,' he said.

The CFA said the blazes are expected to burn well into the night and even after midnight with the westerly change.

'We'll be doing everything we can to minimise the impact of that but we do know it is very risky time for us,' Mr Rankin said.

When asked about how long the blazes would last, Mr Rankin said it could take 'weeks or months' to clear the flames.

'I think all of our longer term forecasts indicate that we are in for a hotter than average and drier than average over the next two months.'

'At this stage, substantial rain is what is required to bring these to a halt.'

Speaking to a press conference before 4pm, Emergency Management Commissioner Andrew Crisp said a change has started to move through the south-west of the state but would not reach Melbourne until about 7pm.

'And it won't be till closer to midnight that we will see the fire, the change on our fires, in East Gippsland,' he said.

'We have been telling people for more than 24 hours East Gippsland is at significant risk in relation to fire.

'Earlier today, we changed our messaging to say that you should not be on the roads. That's what we see now with the potential impact to the Princes Highway.

'So the Princes Highway at the moment is closed between Genoa, near Mallacoota, through to Lake Tyers, with plans underway to further close other sections of the Princes Highway. So the point being - you should not be on the roads.'

Mr Crisp said the bushfires were also creating their own weather.

'We recently looked at the columns, and they're generating their own weather. There's lightning coming out of these columns,' he said.

'It is unpredictable, it's dangerous out there, and people need to stay tuned to their local conditions and stay across that good information so they can make good decisions.'

Andrew Tupper, the state manager for the Bureau of Meteorology, said there were temperatures in the high 30s to low-to-mid 40s across the state on Monday.

'The highest that I've seen so far today has been 45.5C at Hopetoun. In the Melbourne area, we've seen maxima ranging from around 40C to 44C. I'm sure we'll hear some of some more extreme temperatures before the end of the day,' he said.

'So it has been hot, it has also been very windy. For the winds themselves, we've got a severe weather warning out in south-western Victoria. So although we are talking a lot about Gippsland, there are weather impacts across Victoria at the moment.'

Victoria's Police Minister, Lisa Neville urged residents to remain vigilant.

'We cannot be complacent. This is both a message for East Gippsland but for all Victorians,' she said.

'We started the day and we continue to have extreme fire danger indexes in Victoria right across the state. So that means we all need to continue to be alert, be aware of our conditions, and make sure we're following our warnings.'

Organisers of New Year's Eve events across East Gippsland have cancelled the fireworks displays - not the other activities - at Nicholson River, Metung, Paynesville foreshore and Lakes Entrance.

Mr Crisp said on Monday morning it was now too dangerous for people to leave as out-of-control fires took hold of the region.

'If you're not out by 9am, you've got to stay where you are, because there's every chance the Princes Highway could be cut,' he told Sunrise.

'We almost had that for a few hours yesterday afternoon. In fact, the highway was closed for a few hours with a new fire near Cann River.

'We saw the fire travel 26 kilometres overnight, a column that was punching 14,000 metres into the air.'

Mr Crisp reiterated that residents should not be in East Gippsland on Monday amid the dangerous conditions.

'We definitely have a traffic management plan for the highway,' Mr Crisp said, adding that once the fire starts to move the highway will be shut and 'people will be stuck'.

The Princes Highway was temporarily closed overnight after a new fire, started from lightning, was punching a column 14 kilometres in the air creating its own weather, Victoria Commissioner Andrew Crisp said on Monday.

'This is a high-risk day for Victoria, it is a day we don't often see,' Mr Crisp told ABC TV.

'The state is dry and it is going to be very hot and windy. People, get out now. If you don't, you have got to stay across the conditions and listen to the warnings during the day.'

Despite the danger, East Gippsland Shire Council mayor John White told ABC radio it wasn't a 'mass exodus'.

'I have been driving the Princes Highway early this morning and I have met a few boats and trucks but very light traffic really. The same thing yesterday,' he said.

Lakes Entrance Recreation and Camping Reserve caretaker Darren Martin said the message to leave hadn't quite stuck with holiday-makers.

'All of the people in our caravan park have been coming back and forth for years and seem to think they would bunker down and just hope for the best,' he told 3AW.

'There's really only one way in and out of Lakes Entrance.'

Pete, a man who works at the Marlo Hotel near Orbost, said locals who received the warning text for the East Gippsland fires said they thought it was 'a bit of a joke'.

'It's a bit like the boy who cried wolf,' he told The Guardian.

'But the authorities are bedevilled if they do and bedevilled if they don't. If they don't tell people to get out and there's another fire, and everyone tries to evacuate at once, that will be a problem.'

Pete added the hotel had some cancellations and the bushfires could have a large financial impact on the local businesses.

More than 70 helicopters and planes will be working on Monday if conditions allow.

East Gippsland Mayor John White said bushland in the region was bone dry after three years of drought.

'Hopefully people heed the messages. You can rebuild homes, sheds and fences but life is irreplaceable,' he said.

But many are taking little notice of the warnings.

Managers at holiday parks within the East Gippsland region, particularly at the Lakes Entrance, said most of their customers were opting to stay and had taken a relaxed approach.

'We know that some people have left, others are staying,' Iain Podd, who remains at a holiday park on the edge of the fire zone, told The Australian.

'The receptionist here has told us that the direction of the wind means we won't be affected. But of course we will move on if the situation changes.'

Michael Smits, who manages the Big 4 Whiters Holiday Village at Lakes Entrance, said just six of the 67 groups staying there had evacuated.

'Many people are saying that they're going to hang about town, go to a cafe, perhaps go to the beach or wander up and down The Esplanade. There's certainly no panic,' he said.

Others said they have chosen to stay put because a mass evacuation would cause chaos on the roads.

'Thirty, forty thousand people onto the Princess Highway at once. That's just chaos - an accident waiting to happen. Emergency services couldn't keep up - and neither could the road,' one holidaymaker told Seven News.

Victorian Premier Daniel Andrews posted a Tweet on Sunday urging tourists to leave.

'If you are in East Gippsland you should leave today while it's safe to do so,' Mr Andrews posted.

'Residents should activate their fire plan and consider staying with friends and family outside the area. If you are visiting, you should leave today. Please DO NOT travel to the area.'

The extreme weather conditions forced Falls Festival in Lorne to cancel the remainder of the acts.

About 9,000 festivalgoers were sent home as the region braces for severe weather, including winds up to 100km/h and storms.

In a statement on Sunday morning, festival organisers Secret Sounds said conditions posed a risk to health and safety.

'It is with a heavy heart we have had to cancel the remaining days of The Falls Festival in Lorne due to the predicted extreme weather conditions forecast for Monday December 30th in the Otways and surrounding region, creating a risk to health and safety due to potential fires, smoke, severe winds and tree hazards.

'The decision has not been made lightly, our patron and staff safety is our priority,' the statement said.

Prime Minister Scott Morrison, who was in Sydney announcing compensation for NSW volunteers on the fire grounds, said other states were also on his mind.

'We are seeing a real difficult situation emerging in Victoria where we know of the weather conditions particularly changing over the next few days,' he said on Sunday.

'I want to assure Australians outside New South Wales ... our attention is equally there and ensuring the coordinated effort across states and territories is being put in place.'

This bushfire season has already taken nine leaves and destroyed more than 1,000 properties along much of the east coast of Australia.

The blazes have shown no sign of slowing down.

Dangerous fire weather and poor air quality are forecast for NSW as firefighters brace for deteriorating bushfire conditions ahead of New Year's Eve.

The Bureau of Meteorology says temperatures will start building on Monday and are likely to climb past 40C in western Sydney and parts of regional NSW by Tuesday.

'Conditions will deteriorate again as it heats up on Monday with very high to severe fire dangers forecast for areas of the state,' the bureau said on Sunday evening.

The NSW environment department is forecasting poor air quality in Sydney on Monday, warning that pollution will be 'unhealthy for sensitive people', particularly those with heart or lung diseases.

RFS commissioner Shane Fitzsimmons says deteriorating weather conditions could result in 'extreme' fire danger across large parts of the state by Tuesday.

'We can expect a broad geographic area of extreme fire danger ratings, which will extend through places like the southern ranges, the Illawarra south coast and probably down through to the Monaro area, down through the high country,' he told reporters on Sunday.

Severe fire danger ratings are in place on Monday for the southern Riverina, southern slopes, Monaro alpine region, southern ranges and far south coast.

Total fire bans are also in place for large chunks of eastern and southern NSW.

'Deteriorating conditions are forecast the next few days with expected high temperatures and strong winds,' the RFS said on Sunday evening.

'If you have plans to travel through or are staying in bushfire prone areas during this time you should consider the risk, monitor changing conditions and be aware that roads may be closed without warning.'

The NSW Rural Fire Service says Sydney's New Year's Eve fireworks display is unlikely to be canned despite concerns about bushfire conditions.

The Country Fire Service is on high alert as catastrophic bushfire conditions return to South Australia on Monday, with strong winds risking bushfire breakouts.

The temperature is forecast to reach 40C in Adelaide on Monday, with some regional centres to get even hotter.

But it's a cool change in the afternoon that is causing the most concern, with strong and shifting winds set to heighten the risk of bushfires spreading.

The Country Fire Service is particularly worried about the potential for breakouts from the Adelaide Hills fire, and from a blaze on Kangaroo Island that continues to smoulder.

The Adelaide Hills fire has already burnt through 25,000 hectares and destroyed more than 80 homes since it was sparked amid similar conditions 10 days ago.

CFS chief officer Mark Jones said it was regrettable that the same conditions had returned so soon.

'The potential for hot-spot breakouts tomorrow is incredible across the whole fire zone,' he said.

The catastrophic conditions will stretch across the Adelaide Hills, through the mid-north and across to Yorke Peninsula.

Other areas of the state will have either extreme or severe warnings in place.

Tasmanians have also been urged to remain alert to fire risks as the state faces 40C temperatures in southern and eastern areas.

Hobart is forecast to reach 40C and Launceston is expecting a maximum temperature of 34C on Monday, with thunderstorms and wind gusts of 80 to 90km/h also forecast.

The forecast combination of heat, thunderstorms and wind gusts have triggered extreme and severe fire dangers warnings across the state.

'A total fire ban has been declared across the state and is set to continue until Tuesday morning,' Emergency Management Minister Mark Shelton said.

'People are being urged to remain vigilant. It is vital that people know what to do if a fire threatens their home or property.'

Tasmanians were also encouraged to have a plan to keep in touch with older or sick relatives, friends and neighbours.

Tasmania Fire Services recommended people living in bushland areas to relocate to urban areas for Monday, and campers to reconsider their plans.

'As far as the fire danger goes, tomorrow has the potential to be a very bad day across large parts of the state,' TFS chief officer Chris Arnol said.

'Although Tasmania's fire agencies are well prepared, people can't expect to see a fire truck in every driveway and an aircraft above every house.'