Despite the arrival of several cases of the Omicron strain in the country, Defence Minister Peter Dutton said Australia was still one of the safest places to be during the pandemic.

“We can’t close down each time there’s a new variant, and we need to keep those vaccination rates up,” Dutton told Sydney’s 2GB radio on Thursday.

“(Australia) is a safer environment for people than in many other places in the world.”

A seventh returned traveller in NSW has been diagnosed with the Omicron Covid-19 variant and health authorities fear the person may have contracted the virus on their flight home, given they had not been in any of the southern African countries of concern.

While the arrival of the Omicron variant has led to the delay of the return of international students and visa holders, the government is committed to reopening when it is safe to do so.

“We don’t want to lose the many gains that we have made in recent months. But I’m pretty confident that the borders will reopen safely,” Treasurer Josh Frydenberg told the Nine Network.

“More of those skilled workers will come in, more tourists eventually will come in, and of course we will get to living with this virus.”

Visa holders were initially set to return to Australia without the need for travel exemptions, but the date has been pushed back until December 15, due to Omicron.

Additional quarantine restrictions have also been enacted for other overseas visitors.

International arrivals are required to quarantine for 72 hours, while Australians returning from southern African countries need to quarantine for two weeks.

Prime Minister Scott Morrison has insisted a return to harsher domestic restrictions is not an option to deal with the Omicron variant.

While the new variant appears to be more transmissible than the Delta variant, there is an indication the strain causes a milder infection.

NSW recorded 271 new infections overall on Thursday, while Victoria recorded 1419 infections and 10 more deaths.

South Australia has reported 18 new Covid-19 cases with the outbreak forcing the state’s new governor and the opposition leader into isolation.

Chief Public Health Officer Nicola Spurrier said 16 of the new cases were linked to a school reunion event at suburban Norwood last weekend.

The other two involved travellers from interstate.

All cases who attended the Norwood event were fully vaccinated. Former SA premier Jay Weatherill was among them and has tested positive.

There were eight new cases in the ACT while one was detected in Queensland.