Prime Minister Scott Morrison has urged the NRL to ban players who refuse to get a flu shot before the season resumes on May 28.
As players return to training this week, the NRL said it will be compulsory for footy stars to receive the vaccination as part of its strict biosecurity measures to protect against the spread of COVID-19.
But Gold Coast star Bryce Cartwright is reportedly refusing to follow that directive. The back-rower is one of the code's most high-profile anti-vaxxers and he and wife Shanelle revealed last year they would not vaccinate their children.
• Covid 19 coronavirus: NRL star Bryce Cartwright's anti-vax wife speaks as he faces ban for not getting flu shot
• Watch: Penrith Panters statement on Bryce Cartwright '$50,000 abortion' scandal
• Former girlfriend of Penrith Panthers star Bryce Cartwright paid $50,000 for abortion
• League: Bryce Cartwright allegedly involved in deal to pay woman $50,000 to have an abortion
Speaking to Ray Hadley on 2GB radio, Morrison said players should not be allowed to take to the field if they don't receive a flu shot.
"When I was social services minister I started the 'no jab, no play' rule into the childcare facilities and I think the same rule applies there (in the NRL)," Morrison said.
"No jab, no play."
Cartwright will now have to front the NRL and the league's chief medical officer Dr Paul Bloomfield to explain his position, and may have to sign a waiver before he can play.
There is overwhelming scientific and medical evidence to support vaccinations but on Tuesday night, Shanelle defended her family's stance.
"People have the freedom to say what they like, just like we have the freedom to choose which medical procedures we undergo, but ultimately the proof is in the pudding," she wrote on Instagram.
"Our kids are a picture of health. They've never had an ear infection, never had a chest infection or bronchitis, they have no neuro-developmental disorders or auto-immune disorders and are rarely ever sick.
"They've never had a round of antibiotics are any other pharmaceutical drug for that matter (yes, including Panadol). 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."
Former Cronulla prop Martin Lang said it was "unacceptable" Cartwright would reject a flu shot, while legendary Balmain Tigers fullback Garry Jack tweeted: "This is unlike any other year and any other flu season. Time to put others first."
Speaking on the Big Sports Breakfast on Wednesday morning, South Sydney hooker Damien Cook said Cartwright was not the only anti-vaxxer in the NRL.
"There's a few players at different clubs as well (who are against vaccinations)," Cook said. "We have one at our club that wasn't quite sure on it.
"There are some anti-vaxxers out there, which is fine.
"Bryce is obviously very outspoken about it but he's definitely not the only one that is an anti-vaxxer in the competition."