Carlos Takam has broken his silence on his looming battle with Joseph Parker, saying New Zealand's rising heavyweight has made a mistake in taking him on.

With the rival camps finally agreeing to a May 21 date in south Auckland for their crucial IBF heavyweight eliminator, it seems the trash talk has started.

Make that trash tweets, befitting the current state of global communication.

Takam, 35, vowed to knock out Parker and show him 'a real man".

"I respect Joseph Parker, unfortunately it was a mistake for him to take my challenge. I will knockout and show Parker a real man on 21 May," Takam told his social network followers.

Parker, 24, an avid tweeter, was quick to counter-punch, declaring that "talk is cheap" and he wanted their fists to do the talking.

Cameroon-born Takam is currently training at his Paris base while Parker goes through his routines in Las Vegas with trainer Kevin Barry.

Parker has promised to be in "beast mode" for a fight that has huge ramifications.

The winner gets to take on the winner of next month's IBF title fight between American champion Charles Martin and Britain's Anthony Joshua in London.

The fight is starting to make rumbles through the boxing world with The Sweet Science reacting positively to confirmation of the venue and date.

They described Takam as "a major step up for Parker" and "at 35 Takam still has a few years of relevancy left".

They noted that the Transnational Rankings Board, a body independent of the four major boxing organisations, had Takam ranked at No 7 with Parker not in the top 10.

But the respected BoxRec site has Parker at No 12 in their independent heavyweight rankings with Takam at 14.

The IBF, which is all that matters for this fight, list Takam at No 5, one place above Parker.