"At every opportunity he insulted and abused him because that sells pay-per-views. People need to differentiate between the 'real Joe' and the 'Joe doing business'.
"We need Joe to talk in the media, but not so much the New Zealand media - it's all about British media."
Barry was asked if that meant trash-talking.
"I don't think there's a lot of that. What Joe's saying is 'hey, I want the fight, I back my own chin, I've never been down in the amateur ranks, I've never been down as a professional, I've never been dropped in the gym'."
Barry described Joshua as a "money magnet". The 28-year-old filled out Cardiff's Millennium Stadium and London's Wembley Stadium in his last two bouts.
"He's a great fighter who has brought excitement back to what has been a dormant division. Now it's got its punch back.
"The guy puts bums on seat, but he has a lot of flaws. He's stiff and robotic, but also big and powerful with a sledgehammer right hand. There are openings in his defence and he was knocked out in the amateur ranks, knocked out in sparring, and his chin is not as good as Joseph Parker's.
"However, he has a cannon of a right hand. If Joe was moving away in a fight it'd play into his hands. Joe has to step to the fire and back his speed."
Barry also had a couple of other preparation tips for Parker.
"His weight was wrong by at least 10 pounds [4.5kg] in the last couple of fights.
"I don't want Joe to have such a sweet tooth. When he's bigger it slows his foot and hand speed. I need him at about 106-107kg [233-236 pounds].
"I need him mobile because that makes him a harder target. I want him throwing 50-60 punches a round. He needs to be lighter to do that, and I want his hands up higher."
Despite Parker's recent victory over Hughie Fury, his cousin and former heavyweight champion Tyson is an ally.
"He's been a great supporter for Joe," Barry said. "There's a lot of mutual respect. If Joe fought Wilder or Joshua, he'd love him to come into camp with us."
