Prime Minister Scott Morrison used Tuesday's national cabinet to urge state and territory leaders to stick to their reopening plans, despite Omicron raising anxieties about the virus.
Australia will continue its path towards a Christmas reopening while health authorities gather more information about the new strain.
Chief Medical Officer Paul Kelly told the state and territory heads it would be up to two weeks before there was enough information to paint a clear picture about the variant's threat.
But he said there was no evidence vaccines were less effective.
Mr Morrison stressed he is not "spooked" by Omicron, insisting the new COVID-19 strain would not put Australia back into lockdown.
"We're not going back to lockdowns, none of us want that," he said.
All international travellers arriving in NSW and Victoria will need to quarantine for 72 hours and take a COVID-19 test regardless of their vaccination status.
A second test must be taken on day six after arriving in NSW and between days five and seven in Victoria as the states continue their cautious approach to dealing with the new Omicron variant.
All travellers entering NSW from eight southern African nations, or nine in the case of Victoria, will need to quarantine for 14 days.
Visa holders, who were set to be allowed into Australia on December 1, will now have to wait until December 15 to enter the country without an exemption.
The prime minister said a two-week pause on the next stage of Australia's reopening plan was sensible in order for health experts to assess the risk posed by the new variant.
Omicron had also delayed travel bubble arrangements for citizens from Japan and South Korea.
The Australian Technical Advisory Group on Immunisation is examining whether to recommend booster COVID-19 shots sooner in light of the variant.
They are currently recommended for six months after a second vaccine dose.
Home Affairs Minister Karen Andrews said Omicron would lead to new challenges in Australia.
"It's very early days and the world is yet to have a complete understanding of it, we need to know more about it," she told parliament.
"(The two-week pause) was not a decision the government took lightly...we took this decision based on the health advice."
Health Minister Greg Hunt stressed the Omicron variant could be managed.
"All of this is done on the presumption that we will recommence from December 15, but medical advice will guide our decision making throughout," he said.
The latest vaccine figures revealed an additional 95,000 doses were administered on Monday.
It took the total population over 16 being fully vaccinated to 87 per cent, while 92.4 per cent have had their first dose.
More than 430,000 people have received their booster dose.
Victoria has reported 918 new daily infections and six more deaths.
NSW recorded 179 additional cases and three more deaths on Tuesday.
There were six new cases in the ACT.
Australian Associated Press