CANBERRA (BLOOMBERG) - Australia is better prepared than most other countries to face the latest Covid-19 variant of concern, Health Minister Greg Hunt said.

"We are vastly, vastly better prepared than the overwhelming majority of the world, and I say that with great respect to the immense work that's been done globally," Mr Hunt said at a briefing on Monday (Nov 29).

There are two confirmed cases of the Omicron variant in Australia, both fully vaccinated young people from South Africa who were asymptomatic.

Australia on Saturday introduced several new measures aimed at stemming its spread, including suspending direct flights from nine countries.

The government has asked its peak immunisation body, ATAGI, to review the timeframes for booster shots in light of the new variant, which first appeared in southern Africa, Mr Hunt said.

Vaccine supplies are ready if changes are recommended, he said.

Australia's National Security Committee will meet to review evidence and consider actions surrounding the Omicron variant, and a national Cabinet meeting will be held in the next 48 hours, Mr Hunt said.

"We will not hesitate to take additional steps if the medical evidence is that more are required," he said.

Omicron appears to be at least as infectious as the Delta variant, Chief Health Officer Paul Kelly said at the briefing.

But there is no evidence that it leads to a more severe illness.

"The information from South Africa is that it has replaced Delta as the major, possibly the only, virus circulating in that country, quite quickly," Mr Kelly said.

"So, it is transmitting, at least as well as Delta. That seems clear."

There is also no evidence that existing Covid-19 vaccines are less effective against the Omicron variant than other variants, he said.