Anthony Joshua
Joshua and Parker collide on 31 March. Getty

Joseph Parker has told Eddie Hearn to back down on his promise that Anthony Joshua will fight Deontay Wilder in 2018 – insisting the best the Briton can hope for is a rematch against him when he takes his world heavyweight titles this month.

Joshua vs Wilder is one of the most eagerly anticipated bouts in boxing with the 32-year-old American living up to his end of the deal to make it happen after stopping Luis Ortiz in Brooklyn last Saturday to retain his WBC belt.

Joshua meanwhile takes on Parker at the Principality Stadium in Cardiff on 31 March with his IBF, WBA (Super) and IBO titles on the line along with Parker's WBO strap.

The 2012 Olympic gold medallist extending his professional record to 21-0 will surely pave the way for a unification showdown with Wilder, a bout that presents both men with the chance to become the first man in history to hold all four major belts at the same time.

Parker also has that ambition however and has again vowed to inflict a first professional defeat on the 28-year-old.

"I think my plans for the year are I fight Joshua and I beat him and then a rematch so that is my plan for the year," Parker told The Rock radio station, Boxing Scene report.

Like Joshua, Parker boasts a perfect record inside the boxing ring having won all 24 of his professional bouts with 18 of those coming via knockout.

Will many pundits and fans are backing 'AJ' to end that run, the New Zealander firmly believes he has the tools to outbox the Briton over 12 rounds – or stop him early.

"I can outbox Anthony Joshua. I think I have the skills to outbox him but I haven't really shown that," Parker said, as quoted on RadioNZ. "That's why I'm excited - this is a big stage to put on the best performance of my life.

"I can knock him out. I can outbox him. Words can't explain how excited we are. We're fighting in his backyard and we're fighting another champion who's undefeated. That makes it a great fight."