Former Australian WBO and IBO title-holder Danny Green has slammed suggestions Kiwi heavyweight Joseph Parker doesn't have enough "mongrel" in him.

The 26-year-old has lost two-straight fights after he was beaten by Briton Dillian Whyte in London last month.

Former world champion Tyson Fury said Parker was "too nice" and that "he needs to get a bit more venom in him" in a YouTube video.

Speaking to Andrew Gourdie and Jim Kayes on RadioLIVE, Green rubbished the idea Parker isn't aggressive enough.

"He's a real, mellow cat outside the ring and when the bell goes and he jumps over those ropes, he turns into a different beast," he said.

"I don't think there's a problem with his mongrel - he's got that in spades; if you get in that ring you got to be a mongrel, especially at the big stage. You don't get to where he got without having an abundance of mongrel.

"He's calculated, he's very skilful - some guys are different, some guys rely on their wildness and their mongrel. Joseph relies on skill, finesse, technique, power - and he's a different fighter to a lot of guys."

Heavyweight rival Derek Chisora, who knocked out Carlos Takam in the undercard, said Parker should retire after he was asked if he'd be interested in fighting the Kiwi.