Oleksandr Usyk's promoter has implored the WBO to make "the courageous decision" to enforce his mandatory title shot - and delay Anthony Joshua vs Tyson Fury.
Usyk's negotiations to fight Joe Joyce for the WBO interim title have not progressed in two months, Alexander Krassyuk claims, but that has been disputed by Joyce's representatives.
Joshua and Fury are in talks to decide an undisputed heavyweight champion but, with no confirmation yet, Usyk has delivered a reminder of his status as WBO mandatory challenger.
"If AJ vs Fury is not likely to happen this year or is rescheduled until the end of the year, AJ has to make a mandatory defence against Usyk unless he relinquishes the title," his promoter Krassyuk told Sky Sports.
"The WBO has to gather strength and to make the courageous decision - to order AJ vs Usyk.
"And that will be the triumph of justice.
"Otherwise boxing will accelerate its decline in popularity due to unfair and preconceived politics."
Sky Sports revealed in January that Usyk had received a letter from the WBO confirming that the governing body planned to sanction Joshua vs Fury.
Usyk is the mandatory challenger to the belt held by Joshua so was a potential stumbling block in the proposed mega-fight with Fury.
Instead, Usyk and Joyce (the WBO's No 2 ranked contender) began talks to fight for the interim title and a future opportunity at either Joshua or Fury.
But Usyk's promoter Krassyuk now says: "Usyk cannot make any move as there's no certainty around.
"Usyk is doing well, safe and sound, fit and working hard. And is ready to face whoever the WBO legally nominates.
"But my last conversation regarding Joyce took place in the middle of January. I talked to George Warren [part of Joyce's promotional team]. Since that time, we have hardly moved anywhere."
Adam Moralee of SJAM Boxing who manage Joyce told Sky Sports: "I can confirm that SJAM are in conversation with [Usyk's manager] Egis Klimas about the Usyk vs Joyce fight.
"The management teams of the fighters get on well and talks are progressing. Frank Warren is looped in across all matters as Joe's promoter of record."
Usyk's promoter Krassyuk claimed that a lack of clarity over how to divide the purse is holding up a fight with Joyce.
"The problem is that there is no frame for negotiations as the split has not been officially confirmed by the WBO," he said.
"The split should be defined as the average of the last three fights of both fighters.
"And according to my knowledge, it should look like 93 percent in favour of Usyk.
"The minimum allowed by the WBO is 80/20.
"Unless the split is officially fixed, any negotiations make no sense as they would not lead to an agreement."
Sam Jones, Joyce's manager, told Sky Sports: "We understand that Usyk has one fight left with Alexander Krassyuk and so he is trying to push this fight towards a purse bid with [promoter] Eddie Hearn so he can keep himself involved.
"As for his talk about a 93/7 split, that is clearly ridiculous. We have the utmost respect for the WBO, one of the fairest sanctioning bodies in boxing, and we are sure they will come to a fair and appropriate purse split if the matter does go to purse bids."
Krassyuk replied: "I have to keep myself involved as even though it's our last fight, the contract is still active and my obligations towards Usyk remain the same as of the last seven years. And by the way, conducting negotiations behind a promoter's back is a violation of the contract. And I do not think either Egis or Usyk will confirm the violation."
The proposed fight between Usyk and Joyce is seen as one of the major hurdles being solved on the road to Joshua and Fury deciding the heavyweight division's No 1.
"So as of now, we are waiting for the bigger fight (AJ vs Fury) to be either announced or postponed," Krassyuk said.
"That would direct our further steps either to commit with the champ or to fight for the interim title.
"Any option is acceptable once it is made fairly and in accordance to the rules."