Like a rat up a drainpipe, Razvan Cojanu has scampered all the way to Auckland to get his shot at the WBO heavyweight title.

Yet the same can't be said of Hughie Fury, whose injury withdrawal from a May 6 title fight with Joseph Parker had Kiwi promoters Duco Events scrambling.

The 30-year-old Cojanu, a regular sparring partner of Parker, was confirmed on Wednesday as the Kiwi champion's fill-in title challenger.

According to Duco boss David Higgins, there was no negotiating or haggling from the lofty Romanian - he jumped on the first flight to New Zealand.

"That's dangerous, especially when you've trained to fight someone with a different skill set," Higgins told reporters.

"He must be hungry. If we serve up a bunny, people won't buy - cancelling would've looked better but our matchmaker went to work and it was a relief Cojanu stepped up."

Cojanu, who stands at 202cm, is slightly taller than Fury but less awkward, and packs a meaner punch via his thumping left hook.

He was tasked with imitating the cumbersome Fury - and earlier, the vanquished Alexander Dimitrenko - for the Parker camp's pre-fight preparations.

Parker's trainer, Kevin Barry, said the WBO No.14-ranked Cojanu may know more about his protege than any other heavyweight fighter, spelling trouble.

But all other options - from WBC champion Deontay Wilder to Dominic Breazeale - were unable to commit to the prearranged May 6 date.

"When we were placed in this situation last Sunday, we looked at the top 15 guys in the WBO and fighting Razvan was one of our least preferred options for the simple fact we've had (him) in two training camps," Barry said.

"We actually looked at Razvan a couple of times as an opponent and never took that route - that speaks volumes."

In regards to the withdrawn Fury, Higgins said his company would hold no grudges and hoped to arrange a new bout with Parker in the future.

But it would have to be on Duco's terms, or not at all.

"If you can fight that opponent and the terms are right, we'll fight that opponent, and sometimes the adversarial fights are the biggest," Higgins said.