Serena Williams and Caroline Wozniacki donate items to Australian bush fire relief

The dress Serena has donated to raise money for the Australian bush fires.

Serena Williams' autographed dress, a tennis ball signed by the former world No. 1 and Caroline Wozniacki, and a training session with Williams' coach are up for grabs.

The donated items, along with the best seats in the house to the ASB Classic, are being auctioned to raise money for the Australian bush fire relief efforts.

So far raised almost $14,000 has been raised by New Zealand's premier tennis tournament.

One auction features a giant 25cm tennis ball signed by doubles partners Williams and Wozniacki, both former No. 1s.

Williams and Wozniacki have autographed a giant tennis ball to raise money for the Australian bush fires.

Another auction is for a bespoke maroon Nike playing dress, signed by Williams, and worn by the tennis great during her battle with fellow American Christina McHale during Thursday's match.

Unfortunately for one bidder who asked if it comes in "post tournament condition", the dress has been washed.

But it does come with a letter of authenticity signed by Tournament Director Karl Budge.

The dress is descried as an "exclusive item".

"This is a highly prized piece of sporting memorabilia and should be highly desired by sporting fans."

At 1.30pm on Friday, the bidding was up to $3500 but has another eight days to run.

Serena Williams has donated one of her dresses to raise money for the Australian bush fires.

And for those who missed out on centre-court action tickets, the Classic has also put "the best seats in the house" up for grabs.

The tournament built a new stand for the seats overnight and will be auctioning the seats throughout the weekend and into the mens' matches next week.

Budge said the tournament, its sponsors and the players wanted to raise as much as they could.

"It is heart breaking to see the devastation the bushfires are causing to our friends in Australia.

"We wanted to give the tennis community an opportunity to help do our part."

Budge told the Herald all the players and the sponsors had come together to "think outside the box" about what they could donate.

"Everyone's just been incredible really. It's nice to see in times of need just what humanity can do for all of us."

The Classic has also put a one-hour training session with Williams' coach, Patrick Mouratoglou, which can be used by up to four people.

"Balls will be provided. Bidders will need to provide own racquets and wear suitable non-marking footwear," the auction says.

All proceeds will go to the Australian Red Cross in support of the Australian Bushfire Relief.

The tournament will keep putting items up for auction as they get offered throughout this week and next.