Treasurer Josh Frydenberg expects the jobless rate to rise to about 5.4 per cent, up from 5.1 per cent in February.

The figure was calculated in mid-March, meaning it will not reflect the full impact of mass business closures and job cuts.

Treasury has forecast Australia's unemployment rate to rise to 10 per cent as a result of the pandemic.

More than 800,000 businesses have already applied for the JobKeeper wage subsidy program and hundreds of thousands of people have signed onto the JobSeeker payment.

Overnight, Mr Frydenberg and his G20 counterparts agreed to continue coordinating financial and health responses to the virus.

They discussed the need to keep borders open to allow the free flow of medical equipment, as well as ensuring free trade continued beyond the pandemic to keep global supply chains strong.

'We do not want to see a reversion back to protectionism," Mr Frydenberg told ABC radio.

The treasurer told his international colleagues the world could not be complacent on the economic front, just as countries could not afford to relax in the health fight against coronavirus.

The meeting of the finance ministers and central bankers from the world's largest economies comes on the heels of the International Monetary Fund warning Australia - and the globe - is headed for a recession as deep as the Great Depression.

"The world will judge the G20 on our ability to ensure global economic and financial stability throughout this unprecedented crisis," Mr Frydenberg told the meeting.

Governments had to remain responsive, flexible and ready to do more and to make sure that finance was available to all countries.

"Now is not the time for complacency given how rapidly this situation has evolved and how far into uncharted territory this virus has taken us," the treasurer said.

"As we take actions to safeguard our economies, we must resist the temptation to take measures which constrain global supply chains and restrict trade, especially for vital medical supplies and other essential goods.

"Such commitments will give markets the investment certainty and confidence they need during these challenging times."

He applauded the toolkit that the IMF, the World Bank and other multilateral organisations had assembled.

Mr Frydenberg also expressed his pleasure that countries had been able to work collaboratively and in record time to coordinate the actions of central banks so as to stabilise markets and improve access to emergency financing.

The IMF forecast the Australian economy would shrink by 6.7 per cent this year then grow 6.1 per cent over 2021, ultimately leaving it smaller than it was at the end of 2019.

Unemployment was tipped to rise to an average of 7.6 per cent in 2020 and 8.9 per cent in 2021.

But Mr Frydenberg said these figures didn't take into account the full extent of Australia's support package and its efforts to flatten the rate of coronavirus infections.

Mr Frydenberg will follow up the G20 meeting with another with his counterparts involved in the IMF on Thursday night.

Australian Associated Press