Joseph Parker has accused Anthony Joshua of a lack of respect over his refusal to speak to media from New Zealand and Samoa at a workout on Wednesday.
The 26-year-old, who next Saturday fights Joshua at Cardiff's Principality Stadium in a unification fight for the WBO, WBA and IBF heavyweight titles, insists his compatriots deserved better treatment.
Joshua concluded his media duties before those from New Zealand and Samoa had spoken to him, and after a period in which Parker felt he had been particularly accommodating to those from Britain.
It remains unclear whether Joshua's perceived snub was deliberate, but Parker said: "It's a little disrespectful because they've travelled a long way to come and see him, and they respect him, as a fighter and what he's achieved. But it's a little disrespectful.
"We were in camp in Vegas, we had a lot of British media come over and we were very friendly. Being ourselves, inviting them into our home and making them some nice food, which I was very sad to see because I was eating other food.
"He should just be a bit more respectful in talking to everyone who was there. Hopefully in future he can make it better."
Parker can be backed as the 6/1 outsider.
The undefeated WBO champion is also adamant that he has finally overcome long-term elbow injuries following surgery in early December, and that for the first time he has been able to train and therefore fight to his full potential.
Beyond Wladimir Klitschko, Parker was already considered Joshua's toughest test, and he insists he has significantly benefited from the improvement in both his elbows and shoulders.
"We tried to schedule in surgery numerous times, but opportunities came up so we pushed back, and the past two years we've been training and fighting below 100 per cent," said Parker, who travelled to Manchester to defeat Hughie Fury in September.
"Since the surgery there's been a lot of benefits. We've been training with no injuries; this is the best camp we've had for a long time, and that's why we're so confident in putting on a great display and a great fight.
"I feel like I'm in the best shape I've been in. My face is a bit skinnier, and I'm also starting to see some abs come along."
His trainer Kevin Barry added of his improvements since surgery: "The pain Joe had to go through: how he was even able to achieve some of the successes he's had is mind-boggling.
"The surgeon sat down when he looked at the initial damage and said 'How was he able to perform at an elite level?'."
The heavyweight's promoter David Higgins then warned the judges of the importance of scoring the fight fairly, even though Fury felt Parker was wrongly awarded victory when they fought.
"We're grateful to the British Boxing Board of Control, this time they've opted for a balanced panel," said Higgins. "That means a neutral referee, from Italy, a neutral judge from the United States, one judge from the UK, and one judge from New Zealand.
"This fight is so big, and there's so much scrutiny on the officials, they should know they won't work again if they favour the home man obviously."