Prime Minister Scott Morrison says players who refuse to get a flu shot should be banned from competing in the NRL.

Mr Morrison was adamant players should abide by a "no jab, no play" policy after Gold Coast player Bryce Cartwright polarised the rugby league community with his anti-vaccination stance.

Cartwright rejected a request to be vaccinated as part of strict measures to restart the NRL competition on May 28 and must now explain his actions to NRL chief medical officer Paul Bloomfield.

"When I was social services minister I started the 'no jab, no play' rule into the childcare facilities," Mr Morrison told 2GB radio.

"And I think the same rule applies there — no jab, no play."

An NRL spokesperson said players who refused to receive the shot would be dealt with on a case-by-case basis in consultation with club and NRL medical staff.

While reports claimed Cartwright faced a ban, the NRL spokesperson refused to speculate on possible penalties if a player could not justify refusing to have the shot.

The NRL said it was not aware of any other players rejecting the flu shot.

A Rugby League Players Association (RLPA) spokesman said a player who refused to be vaccinated had the option to sign a waiver in order to continue to train and be available for selection while their case was dealt with by the NRL.

The spokesman said the RLPA strongly recommended flu shots but believed players who refused should be dealt with case-by-case and that the vaccination was not mandatory.

The league community appeared to be split down the middle by Cartwright's stance as the majority of NRL teams returned to training on Wednesday.

NRL great Paul Gallen backed the Titans star.

"I'm not against the flu shot, but I just think if they don't want to have it, they don't have to have it," he told 2GB's Wide World of Sports Radio.

"If they don't want to put it into their body, they don't have to have it."

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But Penrith legend Mark Geyer was adamant Cartwright should get the jab if he wanted to play.

"I respect he and his partner's decision for his family, if they don't want to get the kids vaccinated that's fine," he told Triple M's Rush Hour.

"As for Bryce, I'm sorry but no flu shot, no play."

Cartwright's partner Shanelle justified their position on social media.

"People have the freedom to say what they like, just like we have the freedom to choose which medical procedures we undergo," she posted on Instagram.

"But ultimately the proof is in the pudding. Our kids are a picture of health.

"They've never had an ear infection, never had a chest infection or bronchitis, they have no neurodevelopmental disorders or autoimmune disorders and are rarely ever sick.

"They've never had a round of antibiotics or any other pharmaceutical drug for that matter … As parents we do our best with what we know, for some, health comes in a needle and it works for them.

"What we're doing is going seemingly well seeing the state of their health. So if it's not clear, we're not anti anything.

"We stand for medical freedom and the right to choose. Anyway, that's my piece."

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