Elton John, the Marvel star Chris Hemsworth and the heavy metal act Metallica are the latest big names to donate significant amounts to the Australian bushfire relief effort, with John and Hemsworth each committing A$1m (£523,000) to the cause.

John announced his donation while on stage during a concert in Sydney on Tuesday, saying people should be “in awe of the work the firefighters are doing”, before pledging to send A$1m to help with the relief effort.

Elton John: ‘There are people out there who have lost their lives’. Photograph: Jordan Strauss/Invision/AP

“There are people out there who have lost their lives trying to save homes, there are people who have lost their lives and their homes,” the singer said. “And lastly, there’s the plight of the animals, a loss of their habitat that frankly is on a biblical scale and it’s heartbreaking.”

Hemsworth, who was born in Melbourne, encouraged people to “chip in” with donations during an Instagram video in which he also confirmed he was personally donating A$1m to the effort.

The Avengers actor included donation links to firefighting organisations and charities – including the Australian Red Cross, New South Wales regional fire service and the WWF – which he said were “working flat-out to provide support and relief during this devastating and challenging time”.

Metallica announced on Twitter they would be pledging A$750,000 to be split between the NSW Rural Fire Service and to the Country Fire Authority in Victoria to aid in the relief efforts. They said: “NSW Rural Fire Service is the world’s largest volunteer firefighting organisation and all funds donated during this state of emergency are directed toward services related to and victims of these particularly destructive Australian bushfires.”

The donations come after news that three Australian states (South Australia, Victoria and New South Wales) will be exposed to more dangerous bushfire weather from Thursday. The fires have already burned through 8.4m hectares of land (32,430 sq miles) and caused the death of three volunteer firefighters and at least 26 people. The economic impact of the fires is estimated to climb above A$4.4bn, which was the record set by the Black Saturday blazes in 2009that burned through 450,000 hectares.

A burned house in Batlow, New South Wales, where many people have lost their homes. Photograph: Saeed Khan/AFP via Getty Images

The donations follow those by other high-profile cultural figures who have made significant contributions to the relief effort. Pink said she would donate A$500,000, Kylie Minogue pledged the same amount, while the Australian comedian Celeste Barber has raised more than A$27m for the NSW Rural Fire Service and Brigades Donations Fund.

Nicole Kidman and the American country music star Keith Urban also pledged A$500,000 to the Rural Fire Services, while pop star Halsey played a benefit concert for Melbourne’s Country Fire Authority after the Falls festival in Byron Bay she was due to play was forced to evacuate due to a severe weather warning.