Heed fire authorities' advice, PM urges

People in the path of potentially deadly fires should listen to the advice from authorities, Prime Minister Scott Morrison says.

Immediately after landing in Buenos Aires for the G20 meeting, Mr Morrison said he had been keeping up to date with the Queensland fires on the flight to Argentina.

"I know that a number of the fire warnings have been downgraded but we're in for some pretty heavy weather on the weekend. Very extreme weather on the weekend," Mr Morrison told reporters on Friday morning (AEDT).

"I just continue to counsel all Australians in the affected areas to be listening to the warnings and acting on the advice, taking care and looking after each other.

"While some of those warnings have gone down I will be watching those circumstances very, very carefully."

The prime minister also thanked everyone who has been fighting the fires, which authorities say could be potentially catastrophic.