A firefighter has been killed while battling the Australian wildfire crisis, taking the death toll to 27 people since September.

Bill Slade, 60, was killed by a falling tree on Saturday near Omeo in the south-eastern state of Victoria, with the father-of-two commended for 40 years of service with Forest Fire Management Victoria.

The fires have destroyed more than 2,000 homes and have focused many Australians on how the nation adapts to climate change.

The fire has destroyed homes. Credit: AP

The government led by Prime Minister Scott Morrison has come under blistering criticism for downplaying the need to address climate change, which experts say helps supercharge the blazes.

Thousands of protesters rallied late on Friday in Sydney and Melbourne, calling for Mr Morrison to be fired and for Australia to take tougher action on global warming.

Extinction Rebellion said demonstrations also took place in London, Sheffield, Bristol and Lambeth, as well as in 30 countries worldwide from Argentina to Zambia.

A plume of smoke rises from fire in a huge wood chip pile at a mill in Eden, Australia. Credit: AP

More than 100 activists brandishing signs reading “burning earth”, “Scott Morrison is a fire starter” and “wake up and smell the smoke”, demanded more action to tackle the fires, outside the Australian high consulate at the Strand in London.

The chief executive of Siemens said on Friday that the German engineering company will review its involvement in a coal mine in Australia after climate activists called for it to pull out of the project.

Authorities are using relatively benign conditions forecast in southeeast Australia for a week or more to consolidate containment lines around scores of fires that are likely to burn for weeks without heavy rainfall.

The reprieve from severe fire conditions promises to be the longest of the current fire season.