Professor Kelly said the compulsory 14-day supervised hotel quarantine system had been "extremely effective in controlling any virus that may be coming from other parts of the world."

"We put faith in that," he said, following a meeting of the nation's top medical advisors. "We don't believe there's any reason to change our border arrangements in relation to people coming from the UK."

Professor Kelly cautioned the cause of increased transmission was unclear.

"There seems to be an association with this new virus, but at the same time, it's winter ... there's Christmas shopping, a lot of mixing."

More than 200,000 people have entered Australia since March, and almost 2500 cases have been diagnosed in hotel quarantine. Four cases are of the new variant strain associated with increased transmission.

Professor Kelly said his colleagues were looking very closely at the data on the new strain, but at the moment predicted no change to the timeline for the vaccine rollout - currently planned to start in March 2021.

"There is no evidence at the moment that it interferes with the vaccine," he said. "There is no evidence at the moment that it interferes with diagnostic tests."

There have been thousands of mutations of the virus since the beginning of the pandemic, he said. "It's a moving feast. This is yet another new part of this whole pandemic journey that we're on, in terms of this mutation ... but none of them so far have really been of major concern."

All new cases in Australia are receiving genomic analysis to determine where they started. That isn't happening in the UK where the new strain appears to have originated. Professor Kelly cautioned that how widespread the strain is in the UK is still not clear, so banning UK arrivals would be premature.

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A difference between Australia and countries like France that have closed borders to the UK, is that none of those countries have mandatory quarantine arrangements, he said.

Vaccine distribution plans are expected to be finalised in January. The government still needs to see additional data from Pfizer and AstraZeneca for final approval by the Therapeutic Goods Administration.

"There are several countries in the world that have emergency-use authorisation, because they have emergencies," he says, noting US had 200,000 new cases on Monday.

"We are not going down that pathway because we don't have anywhere near that need right now. But we're certainly not stopping in our preparations."