The next 48 hours will decide whether the mega fight will happen as promoter Eddie Hearn waits on the WBA to sanction the bout for their world title.
Klitschko’s camp are insisting the fight will only go ahead if Joshua’s IBF title and the WBA crown is on the line.
Hearn revealed earlier this week that the terms were agreed for the fight and they were just waiting to see which bodies would sanction the bout.
But the delay over the WBA responding to both camps has put the fight in doubt.
The fight was due to take place on December 10 at Manchester Arena.
But both camps are already looking into alternative options if the WBA do not sanction the bout in the coming days.
Hearn said: “The deal is there but we are awaiting sanctioning from the WBA.
“Both teams have written to the WBA to request sanctioning of our fight, but Wladimir wants the WBA belt to be on the line so until that is approved we cannot move forward.
“We expect news in the next few days, but in the meantime I believe both sides will look at alternative options for December 10 while we hope to get the news we need to make the fight happen.”
British fighter Tyson Fury vacated the WBA and WBO titles last week after revealing he is suffering from depression and also failing two drug tests for cocaine.