Junior middleweight contender Tim Tszyu believes his upcoming fight with Brian Mendoza should have been sanctioned as a unification encounter.

Both men are interim-champions, with Tszyu holding the WBO strap and Mendoza having the WBC's version.

The current undisputed champion is Jermell Charlo, who later this month moves up by two weight divisions to challenge undisputed super middleweight champion Saul 'Canelo Alvarez.

Tszyu and Mendoza will collide on Sunday, October 15, in Australia.

The WBO has already ruled that Charlo will be stripped of the title when he enters the ring for Canelo on September 30 - and Tszyu will be elevated to full champion status. On the other hand, the WBC has allowed Charlo to keep his championship status.

“If Charlo didn’t hold up the division, I should be the full WBO champion and he (Mendoza) should be the full WBC champion. If we’re talking by the books, this should be a unification fight, not interim versus interim. But it is what it is, we fight for the WBO full title," Tszyu told Fox Sports.

Tszyu is currently preparing in Las Vegas.

He admits that his upcoming bout is likely his last on Australia soil - before he begins a full conquest of the United States.

“Just driving past T-Mobile Arena and the MGM Grand, it’s something that I’ve always seen on TV, always dreamed about as fight (venues) for myself,” Tszyu said.

“I see this is my last fight in Australia for a good time. I was lucky enough to keep myself active, keep fighting … and we’ve been able to do that by having that big fan base in Australia and bringing the big fights. But for the next few years, I believe this will be my last fight in Australia for a long time.”