Test cricket's second-most successful bowler, the former leg-spinner has confirmed his "baggy green" cap has been sold through auction for $1,007,500.
Twenty-seven people have been killed so far and thousands made homeless as the huge fires have scorched through more than 10.3 million hectares (25.5 million acres) of land, an area the size of South Korea.
Several towns and communities in the heavily populated southeastern region of the country have been advised once again to be alert and evacuate if needed.
Warne wore the cap throughout his Test career, during which he took 708 wickets in 145 matches.
The baggy green is presented to Australian players when they make their Test debut and they receive just one for their entire career.
The price more than doubled the amount achieved when the cap of legendary batsman Don Bradman was sold in 2003.
Warne, who donated the cap to an online auction site on Monday, was stunned at how much money his gesture had raised for relief efforts across the states of Victoria and New South Wales.
"Unbelievable ... so generous from everyone. Totally blown away," he said on Twitter shortly before the auction closed today.
The 50-year-old is one of many local and international athletes to support the fundraising for bushfire victims, with several cricketers promising to donate a sum based on the number of sixes they hit in Australia's Big Bash Twenty20 competition.
Tennis players in the country for tournaments ahead of the Australian Open also promised to donate money for the number of aces they serve, while Australian players in the NBA committed $750,000 to bushfire relief.
Six-times Formula One world champion Lewis Hamilton said on Thursday he was donating $500,000 towards the rescue and care of wildlife caught in the bushfires.
Local sports organisations have also organised fundraising drives at sporting events, while tennis greats Roger Federer, Rafael Nadal and Serena Williams have committed to an exhibition ahead of the Australian Open, which starts on 20 January.