A new wave of COVID-19 cases is hitting the nation, as experts warn people to remain vigilant and stay up to date with their vaccines as we enter the festive season.

Associate Professor James Trauer, head of the epidemiological modelling unit at Monash University, says there is a surge of COVID-19 infections spreading through the community.

"Vaccination remains our most important defence against COVID, even though the virus shouldn't ruin Christmas this year," he said on Wednesday.

COVID-19 is now an endemic virus, which means it cannot be eliminated and is continuously transmitted.

Surges in coronavirus cases were generally caused by new variants, which meant it was "more difficult than ever to predict" when these waves would peak, Prof Trauer said.

Scientists' view of community transmission is further muddied by a lack of data.

With a marked decline in testing, the daily number of cases does not paint a clear picture of the spread of the virus, though researchers can still use hospital admission numbers and wastewater surveillance to monitor COVID-19 waves.

The severity of coronavirus cases has decreased and fewer Australians are being admitted to the intensive care unit because of high levels of population immunity garnered through vaccinations and natural protection from past infections.

Health Minister Mark Butler says it is a new phase of the pandemic.

"We're seeing pretty regular waves every four or six months," he told ABC Perth.

"Each wave is a little bit smaller than the one before it.

"We're getting better every single time at how we manage it in hospital systems and in aged care facilities."

But he emphasised that the virus "hasn't gone away"

Prof Trauer says Australians should still exercise caution by wearing a mask and testing before interacting with vulnerable people, such as those older than 65 and especially people over 75.

They should also seek booster vaccines as they provide longer-term immunity than reinfection.

"Our most important protection against the effects of COVID is immunity, which can be enhanced through vaccination," Prof Trauer said.

Mr Butler said he was concerned about the comparatively low booster shot uptake, with authorities saying only one quarter of vulnerable Australians have had a recent jab.

"The booster rate is is not what we saw in the first few years of the pandemic," he said.

"I'm particularly concerned that older Australians get out there and get their booster."

New COVID-19 vaccines, which target common variants of the virus, will be made available from next month.

Pfizer's monovalent XBB.1.5 vaccine will be available for use in eligible Australians five and older, while the Moderna monovalent XBB.1.5 vaccine can be used for those 12 and older.

"They're the cutting edge most up to date vaccines, but thankfully the vaccines that are currently in pharmacies and in general practice are ... also very, very effective at protecting you from severe disease or death," Mr Butler said.

Those who had a vaccination this year don't need to get jabbed again.