Alex Leapai spars ahead of his world heavyweight title bout in Germany.
Alex Leapai spars ahead of his world heavyweight title bout in Germany. AAP

Leapai boxed on after league knockout blow

FATHER-of-six Alex Leapai has spent time in prison and been banned from rugby league for life.

But next weekend the former Brisbane bad boy could be the toast of Australia if he drops Ukrainian man mountain Wladimir Klitschko in their world heavyweight title fight in Germany.

Leapai heads to Germany on Saturday with his trainer Noel Thornberry, declaring he will knock out his 38- year-old opponent who puts his WBA, IBF, WBO and IBO belts on the line.

But life could have been so different for the Samoan-born Aussie after he was given a scholarship with the North Queensland Cowboys in 1997, the club sending him to Wynnum Manly where he played a few games in the colts and also in first grade.

He was earmarked as a future NRL front-rower until he ran into trouble with rugby league officials, who delivered their own knockout punch to his blossoming career by banning him entirely from the game.

Yesterday, after being presented with a personalised jersey with the No.1 and his name on the back by his favourite team, the Brisbane Broncos, Leapai told APN he only got into boxing because his rugby league world came crashing down around him.

"I did a few silly things, you know when you are young and stupid. I got banned from footy which is why I am doing boxing," said the 34-year-old, who has knocked out rivals in 24 of his 26 wins from 30 fights.

"I was a very dangerous player on the field. I was pretty much like another Gorden Tallis ripping in and doing my job as a forward, but things didn't happen for me. I was sent off a few times, and it was always for the same thing ... fighting."

He was also sent to prison after being found guilty of assaulting two nightclub bouncers.

Leapai now channels his aggression into boxing and has a chance to create history as the first Australian to be crowned the undisputed heavyweight champion of the world.

To claim the title he will have to beat the man nicknamed Dr Steelhammer, who boasts 52 knockouts from 64 professional fights, and has a 15cm height advantage.

When asked if he has contemplated losing, Leapai suddenly zeroes in on you.

"This fight isn't going the distance. I am going to knock this bloke out," he declared.