Mark De Mori admits he's the B-side on David Haye's comeback single but the Australian heavyweight is adamant he won't be cannon fodder for the former two-time world champion at London's O2 Arena on Saturday night (Sunday AEDT).

Haye (26-2), has been out of the ring for over three years since injury forced him to postpone a rematch with Wladimir Klitchsko - one of only two men to beat him.

Reconstructive shoulder surgery appeared to have ended his career before he announced plans to lace up his gloves again at the age of 35 last November.

De Mori's 30-1-2 record has earned him a top-10 WBA world ranking but he's never faced a fighter of Haye's class and experience and is not expected to offer much opposition to the former world heavyweight champion.

However, the 33-year-old said facing the 'Hayemaker' is nothing compared to the challenges he's overcome to get to the biggest payday in a nomadic career that now sees him based in Croatia via Perth, the US and Germany.

A chronic asthmatic as a child he was also classed as deaf until the age of four before his full hearing was restored following surgery.

He took up boxing after teaching himself moves learned from fight videos watched in his father's garage and had an amateur career that lasted just 11 fights before turning professional in 2004.

He was signed by Don King to fight in the US in 2010 but promises made to him by the wild-haired kingpin of US promoters were broken and he returned to Perth disillusioned with the fight game before opting to give Europe a shot.

"If people knew what I've done to become a professional boxer and the places I've lived they'd be staggered," De Mori told AAP.

"I've flown around the world without a trainer, I had to fight in Germany on my honeymoon with my wife in the corner for three fights.

"She was wiping blood off me after a couple of rounds and I had to pay for the promoter to get me on the show just to get a fight.

"I've done it tough and started to lose my love for boxing. If this fight hadn't come along to be honest I would have found it hard to get to the gym. I think I may have walked away from boxing."

Haye has predicted he'll win in two rounds but admitted his time out of the ring is a valid reason to not take De Mori lightly.

"He's a big guy, bigger than me and I know what he will try and do," Haye said.

"But I've fought many guys that are bigger than me and knocked all of them out."