David Higgins promoter for WBO heavyweight champion Joseph Parker, has lashed out over the claimed 'disrespectful' antics of IBF, IBO, WBA world champion Anthony Joshua.

The two boxers are scheduled to collide in a high stakes unification clash on March 31 at Principality Stadium in Cardiff, Wales.

The tension first began last week, when Parker and his handlers were claiming that Joshua refused to conduct interviews with media members from New Zealand and Samoa, who traveled overseas to cover the fight.

Higgins also claims that Joshua is intentionally showing up very late to press conferences and other related media events.

The final press conference takes place on Tuesday.

Things may get interesting at the press event - as Joshua's promoter, Eddie Hearn, has dared Higgins to make some of his 'trash talking' statements to Joshua's face.

The expected verbal fireworks could take a hit before they even begin. If Joshua shows up late, Higgins is already warning everyone involved that Parker and his handlers will not hang around waiting - they will instead leave. 

"Maybe he thinks he's getting a psychological advantage by being late, we just think it's silly and disrespectful," said Higgins to Sky Sports.

"We will start the press conference on time and we will leave 30 minutes later, and if AJ doesn’t show up, it just shows that he has no respect for the media or the fans, because he's been late 100 times in a row."

Higgins believes the pressure of the contest is finally starting to sink in for the British superstar - which is causing this recent rash of claimed behavior from the boxer.

"He looks like a man under pressure. This is all about performance under pressure," Higgins said.

"You’ve got an unbeaten WBO world champion who's genuinely relaxed and sleeping at night.

"I don’t think Anthony Joshua will be sleeping much this week."