WBO heavyweight champion Joseph Parker (24-0, 18 KOs) is hoping to face IBF, IBO, WBA champion Anthony Joshua (20-0, 20 KOs) in a unification encounter in the first quarter of 2018, but he doubts the contest will happen because both sides are so far apart on money.

Earlier, Parker's promoter David Higgins claimed that he was furious because they were offered far less than what Charles Martin was paid to stake his title against Joshua in April 2016.

He said Martin was paid $5 million for the fight.

Higgins has since spoke with Hearn and received clarification on Martin's purse - but, he says Martin was still paid double of what Parker was offered to face Joshua.

"We have heard rumours about what Charles Martin was paid," Higgins told Sky Sports. "Joseph has said he was offered less than half.

"We've had clarification from Eddie. It was actually a little bit more than half that Eddie offered, but still how can Charles Martin be worth nearly double a unification against an unbeaten world champion named Joseph Parker?"

The fight can still happen, but Higgins cautions that the offer would need to significantly improve.

In recent interviews, Higgins demanded a 60-40 split in Joshua's favor. He's willing to budge a little bit from that position if Parker is treated fairly with the financial terms.

"Yes, absolutely, but it's got to improve a lot," Higgins said. "You never say never, but not a lot [less]. We should work together.

"We want a more collaborative, open book approach, rather than pay us off with a low fixed fee and we don't know what the revenues are. The world wants to see it, we want it, but we won't accept it for what we think is an unfair deal. His [Parker's] frame of mind, we are very aligned, our camp. He wants to fight Joshua, but he knows the deal is not what it should be.

"Joseph Parker's message to Anthony Joshua is: 'I want to fight you. I think I'll win, but I want a fair portion of the pie. It's a big pie and let's share it fairly'."