New Zealand heavyweight David Tua could possibly earn a shot at one of the two Klitschko brothers - if he scores a knockout win over Belarus boxer Alexander Ustinov on Saturday.

Tua meets Ustinov at Claudelands Arena in Hamilton, a hugely challenging bout with Ustinov ranked inside the top 10 in both the IBF and WBA rankings and with just one career loss from 29 bouts.

The Klitschko brothers, Vitali and Wladimir, between them hold all the major versions of the world heavyweight titles.

The Klitschkos' K2 Promotions chief executive Alexander Krasyuk has confirmed that a knockout win over Ustinov could earn Tua a fight against one of the brothers.

"If he wins and he is impressive, then will David Tua get a title shot? Yes. Definitely," Krasyuk told promoters for the Tua-Ustinov bout.

Tua, 40, hasn't fought for two years, and hasn't knocked out an opponent since Shane Cameron in 2009.

Tua has lost 50kg (110.2-pounds) and is at his lightest fighting weight since tipping the scales at 107kg ahead of his win over Cameron.