Kiwi captain Adam Blair has launched a scathing attack on Jason Taumalolo after the Cowboys forward snubbed Kiwi selection in favour of playing for Tonga at the upcoming World Cup.

Blair asked the question of whether Taumalolo was "man enough" after Kiwi coach David Kidwell admitted he hasn't heard from Taumalolo after he decided to defect to Tonga.

"You've got to be a man and own up to what you want to do," Blair told NewstalkZB.

"If you were man enough, you'd make the phone call and tell them.

"He could have told them a couple of weeks ago because I don't think it was a last-minute decision.

"Obviously this was something he was thinking about doing."

Blair also admitted it's going to be hard to trust Taumalolo again.

"At this stage, it feels like we've been let down a lot," he said.

"So do we let them back in the team?"

"You're going to have to find some way to be able to trust them again but does that cause issues and problems that we don't need?"