UK doctor warns 'horse has bolted' on Omicron variant

The UK has recorded 86 new cases of the Omicron Covid variant, as a top scientist warns travel bans come too late.

The UK's total number of Omicron cases is now at 246.

The government has reintroduced pre-departure COVID-19 tests for travellers returning to the UK, saying travel is one of the reasons the new variant is spreading.

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New arrivals will have to show proof of a negative test taken at a maximum of 48 hours before their departure.

However, one of the UK's own pandemic advisers has warned "the horse has bolted" and measures to keep Omicron out of the UK comes too late.

Professor Mark Woolhouse told the BBC that community transmission would drive the next wave of Omicron cases.

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He warned that while the UK's tally of Omicron cases was currently quite small, it was spreading rapidly.

Nonetheless, the UK government has said at this point the country will remain open for Christmas.

In Australia, Victoria Premier Daniel Andrews has said the state won't close its borders due to the Omicron variant.

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As of yesterday there were 15 cases of the new variant recorded in New South Wales.

"Victorians can look forward to these next few weeks in the lead up to Christmas with a real sense of confidence," Mr Andrews said.

"We will not be pursuing an 'Omicron zero' here.

"I don't think that makes any sense."

Mr Andrews said evidence had suggested that while Omicron was more contagious, it was a milder strain of the virus.

He said he had texting NSW Premier Dominic Perrottet regularly, and that both Premiers were working to keep COVID-19 restrictions the same in Victorian and NSW.