More than 110 countries at the World Health Assembly on Monday night backed a resolution calling for an impartial, independent and comprehensive evaluation of the international response to the pandemic.

Health Minister Greg Hunt says the probe needs to protect against the health risks of wildlife wet markets and include all populations or partners.

“We need to learn the lessons from this pandemic and ensure we have the strongest possible global health architecture, with an enhanced ability to prevent and respond to future outbreaks,” he told the assembly.

WHO director-general Tedros Adhanom Ghebreyesus promised a review would come “at the earliest appropriate moment”.

US President Donald Trump supported the probe by retweeting an AAP Newswire/SBS story on the motion.

Chinese President Xi Jinping also backed a WHO-led review and said his country had acted with “openness and transparency and responsibility” all along.

“This work needs a scientific and professional attitude, and needs to be led by the WHO. And the principles of objectivity and fairness need to be upheld,” Xi told the meeting via video.

Xi also said China would stump up $US2 billion ($A3.1 billion) over the next two years to help deal with COVID-19.

But the US administration of President Donald Trump decried an “apparent attempt to conceal this outbreak by at least one member state”.

US Health Secretary Alex Azar did not mention China by name, but made clear Washington considered the WHO jointly responsible for the pandemic.

“We must be frank about one of the primary reasons this outbreak spun out of control,” he said on Monday.

“There was a failure by this organisation to obtain the information that the world needed, and that failure cost many lives.”

Speaking after Azar, Chinese Health Minister Ma Xiaowei said Beijing had been timely and open in announcing the outbreak and sharing the virus’s full gene sequence.

Ma urged countries to “oppose rumours, stigmatisation and discrimination”.

China pledged $US2 billion ($A3.1 billion) over the next two years to help deal with COVID-19, especially in developing countries.

The amount almost matches the WHO’s entire annual program budget for last year, and more than compensates for Trump’s freeze of US payments worth about $US400 million ($A614 million) a year.

WHO director-general Tedros Adhanom Ghebreyesus said the UN body had “sounded the alarm early, and we sounded it often”.

When it declared a global emergency on January 30, there were fewer than 100 cases outside China and no deaths, he said.

-AAP