Ministers could meet as soon as Monday to determine whether new restrictions are needed in England over the new year amid growing concerns that soaring Covid cases could hit public services.

They will be expected to assess new modelling from the University of Warwick, given to the Scientific Advisory Group for Emergencies (Sage) in documents published on Thursday.

Scientists have looked at the effects of a potential return to step 2 restrictions from 28 December or 1 January, lasting either two weeks, four weeks or three months until 28 March. No 10 said the data had not yet been considered by ministers.

Step 2 – part of last year’s roadmap – includes a ban on indoor social mixing, a return of the rule of six, and bars and restaurants only able to serve outdoors.

It comes as new ONS figures showed one in 35 people in England had Covid last week, with 1.7 million people testing positive across the UK. No 10 said officials would continue reviewing the latest hospital data over Christmas but that ministers would not meet again until Monday at the earliest.

“We are worried about workplace resilience,” one government source said. “That’s a key reason to reduce the isolation days [from 10 to seven] but a decision will have to be taken in the round, taking in hospitalisations and severe illness, which should be clearer over the weekend.”

A Whitehall source said any restrictions based on workplace concerns would probably be targeted at sectors rather than being broadbrush but ministers had not ruled out legal guidance coming in next week.

The government’s Covid-O committee, which has been focused on the functioning of services and workplace absences, is expected to review the situation again after the Christmas weekend.

Pat Cullen, head of the Royal College of Nursing, told the BBC there was a “very, very depleted workforce” due to the number of staff forced into isolation.

Dr Jenny Harries, the head of UK Health Security Agency, said there were a number of factors as well as the variant’s severity, that would be taken into account when ministers convene after the Christmas weekend to discuss further restrictions for England.

Despite the soaring cases, hopes have been raised that new restrictions could be avoided after analysis showing the risk of hospitalisation is up to 70% less for people with Omicron compared with those infected with Delta, according to the first UK government study of its kind.

Harries said ministers would need to take a holistic approach about how widespread the impact of case rates was on essential services – as well as numbers being hospitalised.

“Ministers will look at all of the data that we have available – and that isn’t simply what the epidemiology is saying, it’s how it’s impacting society,” she told the BBC.

“So, for example, we have very high rates of individuals off sick – we know that particularly in London, around one in 35 have currently got Omicron. Now that’s having an impact on the workforce. So these are not simply about hospitalisation rates.”

She added that ministers are being kept updated daily and that will continue throughout the Christmas period. “I don’t think we do know yet that this is going to be a significantly less serious disease for the population – the older population – that we are normally most concerned about in relation to serious disease and death.”

The Sage documents found “an apparent slowing of growth rates” which could be linked to self-policing of behaviour. But the papers said there were still “doubling times in most of the country … in the region of two to three days and, importantly, test positivity rates are still rising.”