David Haye insists he will be world champion again

David Haye believes he will become world heavyweight champion once again, despite having retired from boxing.

The ex-WBA champion retired in October after losing to Wladimir Klitschko , whose brother Vitali owns the WBC belt.

"My people are talking loosely with Vitali's people and they have shown a keen interest in a potential fight," Haye told BBC Sport.

"I'm going to stay in shape if that call comes, and if it does come I will be heavyweight champion again."

The 31-year-old was talking about his future after a training session in his south London gym, having paid tribute to Muhammad Ali, who turns 70 on Tuesday.

London-born Haye, who moved up from cruiserweight to win the heavyweight crown against Nikolay Valuev , lost his title in a unification bout when he was beaten on points by Wladimir in July and announced his retirement three months later, on his 31st birthday.

Vitali seems very keen to knock me out

David Haye Ex-world heavyweight champion

The Briton said after the fight that his performance against the WBO, IBF and IBO champion had been affected by a broken toe .

"I've always trained to stay in shape and I train every day," added Haye.

"If there is a fight that pops up - against Vitali or Wladimir - I'll be in shape and be ready to go to war and win back my old titles."

Vitali is next scheduled to fight Britain's Dereck Chisora , while Wladimir is due to face France's Jean-Marc Mormeck, with both those bouts set for March.

"It's down to Vitali," added Haye. "He seems very keen to knock me out. Not only to fight me, but to do what his brother Wladimir couldn't do and put me on the canvas.

"It depends on how much he wants to put me on the canvas."

After beating Valuev in November 2009 Haye defended his title by stopping American John Ruiz the following April, while his other successful defence came against fellow Briton Audley Harrison in Manchester.

Haye, who is a close friend of British number one tennis player Andy Murray, also sent his support to the Scot at the Australian Open.

"It is not a physical thing with Andy - he has beaten all the big guns at one stage or other," said Haye.

"I think he will be the number one player in the world before very long - he is on the right path - and I have a sneaky feeling that the next Wimbledon will be his time and he can go all the way."