Scientists have called for 'more stringent' measures as confirmed cases of the faster-spreading strain have risen by more than 12,000 in the UK – and in London alone - where a major incident was declared - cases topped 10,000 on Sunday.
When asked if he could confirm there will be no more new restrictions in the coming days, Mr Raab told Sky News: “Well, I just can’t make hard and fast guarantees.”
But he insisted "we will have a much better Christmas" than 2020 and "we’re in a better position to enjoy Christmas with loved ones this year" due to the number of people fully vaccinated and the uptake in the booster programme.
“I do think of course, you have heard it from the health secretary over the weekend, I’d echo that people will need to be careful and cautious," he added.
His comments came amid reports that Prime Minister Boris Johnson and Chancellor Rishi Sunak are among several Cabinet ministers pushing back against advice to introduce new restrictions in the coming days and questioned scientific modelling on the Omicron surge, according to The Times.
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The paper reported that 10 ministers resisted a call by the government’s chief scientific adviser, Sir Patrick Vallance, at the weekend for new measures to be brought in as soon as possible to prevent the NHS from being overwhelmed.
Mr Raab would not confirm whether he was one of those alleged 10 ministers but insisted to Sky News that the government's current measures of implementing Plan B and driving the booster jab programme "is the right strategy until we’ve got firmer, harder data.”
Mr Johnson has been presented with three options to tackle the spread of the virus, according to the Daily Telegraph.
The paper reported that they range from guidance asking people to limit indoor contacts, to rules on household mixing, social distancing and a curfew on pubs and restaurants, and thirdly, another full lockdown.
One unnamed Cabinet minister reportedly said the data presented on Saturday by Sir Patrick and England’s chief medical officer, Chris Whitty, was “just trashed by the Cabinet”.
The source said “guidelines, rather than restrictions, are entirely possible”.
However, critics have raised doubts over how likely the public are to stick to new measures as Mr Johnson's government remains engulfed in a series of party scandals - with a fresh photo emerging on Sunday of the prime minister and Whitehall staff enjoying cheese and wine in a Downing Street garden during lockdown in May last year.
It comes after Health Secretary Sajid Javid on Sunday refused to rule out implementing new measures before Christmas, telling BBC One’s Andrew Marr programme there are “no guarantees in this pandemic”.
He said it is time to be “more cautious” and that "at this point we just have to keep everything under review".
Commons Leader Jacob Rees-Mogg later reiterated Mr Javid’s stance, but insisted it was “too early” to forecast whether a recall would be necessary.
He told BBC Radio 4’s Westminster Hour: “Chris Whitty is himself saying we don’t have the full data, they are not yet available, we are getting more information from South Africa that is more advanced in the Omicron variant so it is too early to make these forecasts and it is really interesting that people are doing things for themselves.
“The cancellation of parties, the decisions not to socialise, the cancellations are people realising that they can make choices for themselves. They don’t always need to be told what to do by the Government.”
London’s Mayor Sadiq Khan warned that if restrictions are not brought in soon the NHS could be “on the verge of collapse”, with sickness affecting workforce levels.
Education Secretary Nadhim Zahawi has called on ex-teachers to sign up to help with staff shortages in the new year, while headteachers’ unions have warned of possible disruption to in-person lessons.
Experts have warned against a delay in bringing in measures.
Professor Stephen Reicher, a member of Scientific Pandemic Insights Group on Behaviours (SPI-B), said Omicron’s faster transmissibility means it is “coming at us like an express train”, and called for clear messaging to the public.
He told BBC News: “A good, clear message is more important now than ever before of how serious the crisis is.”
Prof Reicher added that “good information from the government, combined with good support from the government” would likely lead to people accepting “the measures that are necessary to bring this thing under control”.
Meanwhile, the Treasury announced on Sunday that extra funding to tackle Covid-19 across Scotland, Wales and Northern Ireland had been doubled to a total of £860 million.
Mr Sunak said the boost – which followed a ramping up of demands from the three nations for more cash support amid the rise in Omicron cases – was to ensure people were supported “in the face of this serious health crisis”.
Advice from the Scientific Advisory Group for Emergencies (Sage), published at the weekend, warned there are likely already hundreds of thousands of new Omicron infections every day in England and that hospital admissions with the variant in the UK are “probably around one tenth of the true number” due to a lag in reporting.
England’s chief nursing officer Ruth May has urged a “final festive booster bounce” for the jabs programme, telling people there is “no room for complacency” and to book their slots – which include availability on Christmas Day.
While a record 830,403 boosters were given in England on Saturday, a rate of around one million a day is needed if every adult is to be offered a booster jab by the end of the year.
Deaths in England of people with the variant have risen to 12, while hospital admissions of patients with confirmed or suspected Omicron increased to 104, according to the latest figures from the UK Health Security Agency.