The 50-year-old wore the cap throughout his 145-Test career, in which he took an Australian record 708 wickets.

At least 24 people have died since the fires began in September.

"Everyone is in this together and we continue to find ways to contribute and help on a daily basis," said Warne.

"This has led me to auction off my beloved baggy green cap that I wore throughout my Test career.

"I hope my baggy green can raise some significant funds to help all those people that are in desperate need."

All money raised will go to the Australian Red Cross Disaster Relief and Recovery Fund, with the highest bid at 07:00 GMT on Monday standing at A$301,500. The auction is open until Friday.

The fires are a natural part of the Australian weather cycle, but have been worsened this year by hotter-than-average temperatures and a persistent drought in many areas.

Warne is Test cricket's second-most successful bowler, with only Sri Lanka's Muttiah Muralitharan (800) taking more wickets.

The 'baggy green' is given to an Australian Test player when he makes his international debut and cricketers usually wear the same cap throughout their career.

Legendary batsman Don Bradman's 'baggy green' fetched A$425,000 (£225,000) in 2003 - the Australian, who died in 2001, has the highest Test average of 99.94 runs.

Tennis stars also pledge financial support

Novak Djokovic, the world number two in men's tennis, has also pledged financial support to the relief fund, matching the A$25,000 donation given by five-time women's Grand Slam champion Maria Sharapova.

Sharapova, 32, asked Djokovic to support the cause after saying on Sunday she would donate, with Serbia's 16-time major winner agreeing to help in a Twitter message to the Russian on Monday.

Australian world number one Ashleigh Barty has already said she will give all of her prize money from the Brisbane International to the relief fund.