"The Gypsy King' says the Ukrainian would be a "lamb to the slaughter" against the elite of the division, despite a flawless professional record.
After a few troublesome moments in the early rounds, Usyk dispatched Brit Derek Chisora last month with relative ease, earning a unanimous decision victory against the power-punching veteran.
That win has guaranteed the London 2012 gold medallist a future fight with Anthony Joshua, who reigns as WBO, IBF and WBA heavyweight champion.
Usyk extended his undefeated record to 18-0, and 2-0 as a heavyweight after a five-year stint as the best cruiserweight in the world.
But WBC champion Fury isn't convinced the 33-year-old can hang with himself, Joshua or even Kiwi Joseph Parker, questioning Usyk's lack of power and size.
"None of us are quaking. Is that it? Everyone’s like, 'Is that what all the hype was about?;" Fury tells talkSPORT.
"On that performance, I can say that none of the top 15 heavyweights out there are sweating Oleksandr Usyk at the moment, unfortunately.
"This is the heavyweight game and heavyweights ain't like they were years ago, and Chisora’s probably the smallest heavyweight out there.
"Being brutally honest, I think when he fights a big heavyweight who can punch a bit, it’ll be like a lamb to slaughter.
"My opinion of it is - it’s the heavyweight division and not the cruiserweight division for a reason."
Fury, unbeaten in 30 professional fights, does credit Usyk for his highlight technical boxing ability.
But says ultimately that won't help him against the power of a top heavyweight boxer who can end the fight in a flash.
"I understand all cruiserweights that do well want to step up to heavyweight to get that big money. They all want a piece of the pie, but there are divisions for a reason.
"After his last performance, I honestly thought he was better than he was because I highly rate Oleksandr Usyk as a master technician as a cruiserweight.
"But at heavyweight, there was nothing that impressed me to be fair."
Fury's return to the ring has been the subject of much conjecture in recent weeks. A planned rematch against former WBC champion Deontay Wilder has been scrapped after the American let a guaranteed rematch clause expire.
Fury was tipped to wait for the outcome of Joshua's December showdown with Kubrat Pulev, but last week he announced a title defence against Agit Kabayel, slated for December 5 in London.
Photo supplied Caption : Heavyweight boxing kingpin Tyson Fury