"We're close," Hearn told Sky Sports UK. "We're at a stage now where we're having to compromise on certain points that we don't really want to, but ultimately we're going to have to because if you want to fight Anthony Joshua, these guys - they want to be overpaid."
"He is the golden ticket fight, the 'Willy Wonka' golden ticket fight that everybody wants and unfortunately for him, it's going to mean sometimes taking a deal that isn't right."
"My job is to represent Anthony Joshua and to deliver the deals that are right. We're not just going to roll over and let them tickle our belly and give everything away, but we ultimately understand that we're going to have to overpay Joseph Parker to get that unification fight," Hearn said.
"It is the right fight for everybody and I think we'll get it made. But we'll see over the next week or so."
Hearn said he wanted the fight details to be sorted out by Christmas, confirming Cardiff's 78,000 seater Principality Stadium would be the most likely venue.
Read more: Bob Arum claims Anthony Joshua and Joseph Parker close to sealing March 31 bout in Cardiff
Read more: Paul Lewis: Anthony Joshua holds most of the cards in potential fight with Joseph Parker
Hearn said he and Higgins had some "quirky venues" on the discussion table but both acknowledged the need for a large crowd with Cardiff's retractable roof providing the best option.
"Like I said, really by the end of 2017, we must be in a position that fight is done and we're ready to move forward," said Hearn.
Parker's promoter David Higgins had been adamant his offer of a 35 per cent split on the net profit and it appears Hearn has now crept closer to meeting demands, offering 30 per cent to Team Parker.
With negotiations on the table Hearn assured they are 'only a couple percent away from making the fight.'
Meanwhile, American Deontay Wilder, who holds the WBC version, has been demanding a 50-50 split with Joshua for a potential fight further down the track.
Hearn said the plan for Joshua would be to fight against Wilder with three belts in hand and ultimately become the undisputed heavyweight champion of the world.
"We need these belts, there is no secret, and they know that as well. Anthony Joshua's pure aim is to become undisputed heavyweight champion of the world. To do that he has to beat Joseph Parker and Deontay Wilder," Hearn told Sky Sports.
"The Wilder fight is in dreamland at the moment, with his demands. The Parker fight is very close. Hopefully, we can get that over the line before Christmas, pick up the WBO title in March, and then move on for the big one against Wilder for all the belts on the line."
"Deontay Wilder is on cloud nine. I mean he's never fought anybody. You've got to understand, Anthony Joshua is making 10 times per fight what Wilder is making, and he wants to make the same money that Anthony Joshua is making in that fight."
"I understand. Wilder is on relatively low money, he's not a draw in the US right now. They all want the Joshua fight. It's everybody's cash-out fight."
Hearn is also trying to fill a February 3 slot in London were it appears heavyweight contender Dillian Whyte could headline.
