Australia has shut its borders to nine southern African countries and suspended all flights from that region amid growing concerns about the new Omicron variant of COVID-19.

Federal Health Minister Greg Hunt says Australia is in a vastly different position to other countries due to high vaccination rates, but precautionary measures are needed against the new strain.

He says all flights have been immediately suspended for two weeks from South Africa, Namibia, Zimbabwe, Botswana, Lesotho, Eswatini, the Seychelles, Malawi, and Mozambique.

Any Australian citizens or dependents who have been been in those countries in the past 14 days must go into mandatory quarantine, and non-citizens who have been southern Africa will be banned from entering Australia.

Mr Hunt says anyone who has already arrived in Australia from any of those nine countries must go into immediate self-isolation.

“There are no known cases of the Omicron variant in Australia,” the minister told reporters on Saturday.

“We’ve taken precautious action in the past, we’ve taken early action in the past, we are doing that again. 

“The difference is that we now have strong vaccines, we have one of the highest levels of coverage in the world, we have one of the most recently vaccinated populations in the world, and we have strong public health and social measures.”

The number of people who have arrived from southern African since November 1 is thought to be under 100.

The latest variant, given the name Omicron by the World Health Organisation on Saturday morning, first emerged in Botswana and has been detected in South Africa, Hong Kong, Israel and Belgium.

It has double the number of mutations as the Delta variant that sparked a third wave of outbreaks and lockdowns in Australia this year.

Chief Medical Officer Paul Kelly said Omicron was spreading quickly in southern Africa, but it wasn’t clear yet that it has more severe symptoms than other strains or if it can evade immunity from vaccines.

“They’re crucial points, it’s the reason why we’re taking this precautionary approach, which is proportionate to that risk,” he said. 

Professor Kelly also said it was premature to be talking about whether domestic lockdowns or further restrictions would be needed to stop the spread of Omicron within Australia.

So little was known about the variant, including which public health measures could be effective in containing it, he said. 

“In terms of ruling in or out what else we might do, as the minister has clearly said, we will do what we need to do at this stage,” Prof Kelly said.

“To move toward speculation about where we might end up with in Australia, even if it came here, and we don’t have it here yet, that is premature.”

Mr Hunt said the new travel restrictions were strong and swift, but precautionary, and they can easily be rolled back or ratcheted up if needed.

The government could close borders and suspend flights to additional countries, he said, if the variant spreads.

“If more actions are required, we will not hesitate,” the minister said.

“Today we have taken those actions, today I’m saying, if the medical evidence shows that further actions are required, we will not hesitate to take them and that may involve strengthening or expanding the restrictions.”

About 86 per cent of Australians aged 16 and older are double-dosed, which means between 72 and 73 per cent of the entire population. Just 1.5 per cent of the country have received a booster shot. 

The federal government is sending letters to every household in the country urging people to get their booster shot six months after becoming double-dosed.

AAP

Get all the latest Canberra news, sport, entertainment, lifestyle, competitions and more delivered straight to your inbox with the Canberra Daily Daily Newsletter. Sign up here.