Samoa-born boxer Alex Leapai says he's never been as well prepared for a fight as he is for next weekend's world heavyweight bout against Ukrainian Wladimir Klitschko.

Klitschko hasn't lost for a decade and will put the WBA, IBF, WBO, IBO and The Ring Heavyweight Championship titles on the line in Germany.

Leapai, who is the first Australian in 106 years to challenge for a unified world heavyweight title, says he couldn't have asked for a better build-up.

"This is the first time I've been able to train full-time. Even in my last fight I was still working and training and I was fighting for a world title eliminator but this fight [I'm] training full-time and everything has gone to plan. Really looking forward to getting over there and doing what I do best. It's not going to be easy but anything is possible. Two more sparring [sessions] left and look forward to leaving on Saturday and get over there and base over there."