Chief Medical Officer Paul Kelly told Mark Butler on New Years Eve that imposing the requirement would be unnecessary and inconsistent with Australia's COVID-19 management.

A day later, Mr Butler announced people travelling to Australia from China, Hong Kong or Macau will need to test negative within 48 hours of departure from Thursday.

People transiting through will not be affected and those who test positive after arriving in Australia will need to follow the local health advice, including the recommendation to isolate while symptomatic.

Mr Butler defended the decision, saying while there was no evidence of an imminent threat to Australia, he was using "an abundance of caution".

He cited the World Health Organisation's call for more data out of China to ensure authorities were able to quickly detect and assess any new COVID-19 variants and he maintained the measure was modest.

"This is a very fast-moving situation and we've seen countries right around the world take the decision I have a couple of days ago," he told Adelaide radio station 5AA.

Mr Butler said similar measures will not be put in place for travellers from other countries such as the United States due to the timely reporting of information and genomic sequencing data.

Professor Kelly said mandatory testing was "disproportionate to the risk" given Australia's high vaccination rates, ready access to treatment for vulnerable people and the lesser risk of transmission in summer.

"I don't believe there is sufficient public health rationale to impose any restriction or additional requirements on travellers from China," he wrote.

He said there was a consensus between state and territory health chiefs as well as New Zealand public health officials.

Prof Kelly suggested testing plane wastewater, voluntary sampling of arrivals, an increase in community wastewater testing and following up with returned overseas travellers who tested positive for the virus.

Opposition Leader Peter Dutton said the government needed to explain why they went against the health advice when there was no new variant of concern coming from China.

"In the absence of Australian health advice to put the restrictions in place, the prime minister must justify why he has deviated," he said.

Beijing recently scrapped strict "zero-COVID" measures in favour of a new policy of living with the virus, which resulted in an eruption of infections and the prediction of three winter waves.

Treasurer Jim Chalmers said Australia already had a big enough challenge managing COVID "without unnecessarily exposing ourselves to a part of the world that's got an extraordinarily large wave right now".

Australian Associated Press