Boxing: Joseph Parker's promoter says fight deal could be biggest in New Zealand history

Duco Boss David Higgins says the heavyweight unification fight between Joseph Parker and Anthony Joshua could be the biggest contract in New Zealand history.

After lengthy negotitations, the much-awaited bout was confirmed overnight and will be held at the Principality Stadium in Cardiff on April 1 (NZ time).

Higgins was pleased with how negotiations went and said they got "very close" to the 35-65 split they wanted.

"The contract ... for a one-off event could be the biggest in New Zealand history and the money for Joe is a one-off," Higgins told Martin Devlin on Radio Sport.

Parker is reportedly set to bank about $12 million from the fight and even more in the rematch should he be successful.

"Based on the budget I've signed off it could be near that. If it does the same demand as Mayweather-McGregor it will be double.

"How long is a piece of string? It's all down to the buildup."

Higgins said there will be large worldwide interest in the bout because of the real rivalry between the fighters.

"All of Anthony's fights have been boring build up because no one quite had the spine to make it real.

"They've always been sort of the underdog that would stick to the opportunity and the money. And they wouldn't dare say that Anthony's got a questionable chin or anything like that.

"Klitchko and Joshua I think is the biggest or second biggest revenue earner in UK history, and Klitchko was a respectable German gentleman.

"The thing about what we're doing, it ain't trash talk it's fact talk. He has been flattened six times, he's got a questionable chin. That is fact and the truth hurts."

A press conference featuring the main protagonists will soon be held in London.