Former Kiwis teammate Benji Marshall has staunchly defended Warriors halfback Shaun Johnson amid calls for the NRL veteran to retire at the end of the season.

Johnson has one year left on his current deal with the Warriors who are struggling in 15th on the NRL table following six straight defeats and the axing of coach Nathan Brown.

Marshall said on the Triple M radio show that the Warriors are wrongly using Johnson at halfback which doesn't suit his game.

"Everyone has this opinion about Shaun and an expectation about the way he plays and I've spoken about it before…he's been taken to the Warriors to be a game manager slash, put their side in good field position and just kick the footy, which has never been his strength.

"I feel like his strength is his running game, and if I was them I would move him to five-eighth," Marshall said.

The NRL great also had a crack at people calling for Johnson to retire. The 31-year-old is playing in his 12th NRL season and signed a two-year deal with the Warriors starting this season.

"On the weekend I heard calls for him to think about retiring - maybe he should think about his legacy and give it away. I say shut up to that. Because that's up to Shaun," Marshall said.

"No one can understand how hard it's been off the field for a lot of the Warriors players especially Shaun not having his wife and his kids with him. I think once he finds peace with that and gets back to his family and he can reassess where he's at. That's up to him whether he wants to retire or not. I don't think he has to go and say 'yip, I'm done this season'. He's not done. If he wants it bad enough he can come back and do it."

"I feel like some of that criticism he cops, okay we understand he's not playing his best or the best that we've seen from him but that doesn't mean he needs to think about retiring."

On talk the Warriors could force Johnson out of his contract at the end of this year, Marshall said that wouldn't be fair.

"That's okay but I don't think it's fair. And if they are thinking about that then maybe find a way to support the guy and help him bring out his best because they're the ones who signed him."