Shane Warne has put his famous baggy green cap up for auction in a bid to raise funds for victims of the Australian bushfires.

Former leg-spinner Warne wore the cap throughout his career in which he played 145 Test matches and took an Australian record 708 wickets.

The 50-year-old announced the auction on his Instagram account on Monday and bids had exceeded 300,000 Australian dollars within three hours.

Warne wrote: "The horrific bushfires in Australia have left us all in disbelief. The impact these devastating fires are having on so many people is unthinkable and has touched us all.

"Lives have been lost, homes have been destroyed and over 500 million animals have died too. Everyone is in this together and we continue to find ways to contribute and help on a daily basis.

"This has lead me to auction of my beloved baggy green cap (350) that I wore throughout my test career (when I wasn't wearing my white floppy hat).

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

The successful bidder for the cap will also receive an autographed certificate of authenticity from Warne.