England's Chief Medical Officer Chris Whitty said the Omicron coronavirus variant posed a really serious threat and that what health officials already knew about was "bad".

"This is a really serious threat at the moment. The how big a threat - there are several things we don't know, but all the things that we do know, are bad," Whitty told a news conference on Wednesday.

"And the principle one being the speed at which this is moving, it is moving at an absolutely phenomenal pace."

He added: "We do have some things going for us this time of which the most important is the existence of effective vaccines and the ability to boost at speed at this stage."

Britain recorded 78,610 coronavirus cases in laboratories Wednesday, the highest daily total since the pandemic hit last year.

France announced yesterday that because of surging Covid-19 cases in Britain only designated categories of people would be allowed to travel between the two countries, and anyone arriving from Britain would have to self-isolate.

Truck drivers will though be exempt from the new rules, the French government said, easing British concerns the restrictions could cause supply chain disruptions.

Malaysia yesterday announced new restrictions, including banning mass gatherings and requiring booster doses for high-risk groups, as it reported its second case of the Omicron variant, reports Reuters.

Health Minister Khairy Jamaluddin said authorities were also verifying 18 more suspected cases of the variant, believed by experts to be the most transmissible yet, with results expected by today.

Indonesian President Joko Widodo urged people to stick to health protocols and ensure they are vaccinated against Covid-19, after the world's fourth most populous country detected its first domestic case of the Omicron variant.

South Korea said yesterday it will reinstate stricter social distancing rules a month-and-a-half after easing them under a 'living with Covid-19' policy, as the number of new infections and serious cases spirals.

Denmark yesterday recommended US drugmaker Merck's anti-Covid treatment molnupiravir for at-risk patients with symptoms, becoming the first EU country to do so.