Brexit Secretary Stephen Barclay told Andrew Marr it was a "fast-moving situation" and the Foreign Office was working with Chinese authorities.

Updated Foreign Office guidance has warned against all travel to Hubei province - where the virus began - and urged Britons to leave if they can.

The virus has so far killed 56 people.

A total of 52 tests have come back negative for the new strain in the UK, the Department of Health said on Sunday - indicating that the results of 21 tests have been concluded since its last update on Saturday.

Hubei province has been on lockdown for days as the authorities try to contain the virus which originated in the city of Wuhan and has infected almost 2,000 people since its discovery.

Some British people in Hubei province say they are stuck and are unhappy with the government response.

'Wuhan being sacrificed'

Tony, from the UK, told BBC News he was en route to Wuhan when travel restrictions were first published by the British government. He is now in the city with his Chinese wife and her family.

He said: "The feeling of many here is that the government are sacrificing the Wuhan people for the greater good of the country.

"The transport situation has made it difficult for people to go to those jobs that should still be done."

Tony said he tried to contact the British Consulate in Wuhan and the UK embassy in Beijing "but the answer phone message has not been updated".

Britons Sophie and Jason, young graduates in Wuhan to teach English, said they had "been stuck in the house for four days".

"We're frustrated by the fact we don't know what's going on," Sophie said. "It's scary."

Yvonne Griffiths, a university lecturer from Cardiff, was due to fly home on Monday, but her family have told BBC Wales the journey has been cancelled.

She said: "I am disappointed at the absolute silence on the issue of how stranded people are going to get home."

Dr Griffths' daughter Bethan Webber said a government airlift would now be her mother's only option.

"Short of the government getting her out there's no getting out," she said.

'Grave situation'

Chinese President Xi Jinping has warned the spread of the virus is accelerating, telling senior officials the country is facing a "grave situation".

Checkpoints in Hubei province are preventing people from leaving, the airport has been closed, and many of the roads are blocked to all vehicles except those carrying patients or medical supplies.

China's health minister Ma Xiaowei told reporters the ability of the virus to spread appeared to be strengthening.

British scientists have said that it may not be possible for China to contain the virus.

Researchers at the MRC Centre for Global Infectious Diseases have calculated that each person is passing the virus on to two or three others.

The scientists, based at Imperial College, London, say the transmission rate needs to be cut by 60% in order to get on top of the outbreak.

In the UK, tests on 31 people suspected of contracting the virus have come back negative, the government said on Saturday.

In its most recent update, the Department of Health said there are currently "no confirmed cases in the UK or of UK citizens abroad, and the risk to the public is low".

Officials are trying to trace around 2,000 people who have flown to the UK from Wuhan in the past fortnight.

On Saturday, Australia confirmed its first four cases - first in Melbourne, and then three more in Sydney.

It has also spread to Europe, with three cases confirmed in France.

China has flown specialist military medical teams into Hubei province and state newspaper the People's Daily reported that a second emergency hospital was under construction, as the virus continues to spread.

Across mainland China, travellers are having their temperatures checked for signs of fever, and train stations have been shut in several cities. Many Lunar New Year celebrations have been cancelled.

From Monday, China is suspending all foreign trips by Chinese holiday tour groups, state media reported.

A nationwide ban on wildlife trade has been welcomed by animal protection groups.

Kate Nustedt of World Animal Protection said she the move would "put a stop to the horrific conditions that serve as such a lethal hotbed of disease".

Meanwhile the US has announced that staff at the Wuhan consulate will be evacuated on a special flight on Tuesday.