'We made an offer to Joshua to fight Deontay in his next fight and we offered him $50 million.
This follows a well-publicised projection from Hearn that the bout could gross well over £100 million from ticket sales and pay-per-view costs.
The American boxer had posted a short video on Twitter showing WBO, IBF and WBA titles holder Joshua, 28, saying he would accept the fight for $50m.
However Finkel makes it clear that until Joshua accepts the sum offered, no negotiations will take place beforehand till a yes is given by the unified world heavyweight champion.
"No disrespect to Deontay but I don't believe he has that kind of money so I want to know where it's coming from and who is paying it".
Fury's impending comeback has fuelled talk of potential duels with Wilder and fellow Brit Anthony Joshua, who now holds the three titles that Fury took from Klitschko in Dusseldorf two and a half years ago.
When asked about the status of the current offer, AJ's promoter continued: "We haven't even seen any paperwork yet so we're gonna request that and we're gonna explore it".
Hearn has also appeared to be steering Joshua, a native of England who has yet to make his USA debut, against unbeaten Jarrell "Big Baby" Miller this summer in Brooklyn, New York.
Indeed, fight fans will be praying that this whopping heavyweight title fight can be made as both teams get set to meet one another on Friday.
Saudi Arabia bans unauthorised use of drones after palace security breach
The statement came after footage was circulated online that included the apparent sound of gunfire in the Saudi capital. Notable clerics also have been detained in a clear bid.
'Anthony, get over with your man Eddie and Barry Hearn and tell them to check their emails, ' he said in a video.
Previously Wilder, 32, said "all the money is in the bag so I expect you will be a man of your word". "If that's the case, Wilder's team, bring me $50 million up front, and we'll take the fight".
Hearn had earlier offered Wilder US$12m (NZ$17.5m) for the fight.
Joshua with his manager and promoter after Joseph Parker fight.
Joshua has been given 24 hours to sign the contract by Wilder's boss Shelly Finkel.
I've had it. Let me tell you, when Christmas is every day it doesn't make you happy.
"In exchange, I'm getting advice on nutrition and how to bulk up a bit and how to look better in myself".
Hearn added: "We really want to do the fight in the UK".