NRL players who refuse to be vaccinated but sign a revised waiver will be permitted to train and play after the ARL Commission ratified the game's biosecurity measures.
A small number of players across the code, including the Gold Coast's Bryce Cartwright and Canberra trio Sia Soliola, Josh Papalii and Joe Tapine are understood to have crossed out a line of the NRL's original waiver.
The section requiring players to agree that they are placed at greater risk of contracting influenza by not being vaccinated is understood to have been amended. Players are now asked to acknowledge they have been advised of the heightened risk in not being vaccinated.
Consultation with the RLPA will continue on the biosecurity measures, with the NRL stating 97 per cent of more than 800 players and staff across the game have been immunised.
"These protocols have been reaffirmed to clubs and players today, including the requirement for flu vaccinations for all players and staff," an NRL statement said.
"The protocols allow for exemptions to vaccinations under compelling circumstances, including requiring players to sign a release. Until an NRL-approved release is acknowledged and signed by players, they will not be permitted to train."
Players have also been told Mother's Day visits to family will not be exempt from the code's strict COVID-19 protocols.
It had been hoped a one-off easing of biosecurity measures could be introduced on Sunday if players' parents could adhere to the same rules – which require self-isolation if they experience any flu-like symptoms.
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But NRL biosecurity experts have declared the proposed Mother's Day visits too great a risk as the NRL targets a May 28 return date.
The game will also delay the resumption of contact training by a few days until next week under the gradual resumption of sport per AIS guidelines.
NRL teams will have the best part of three weeks for full contact training and wrestling drills before round three is scheduled to kick off.
Cartwright has claimed on social media that he has never said he was "anti-vaccinations".
"I've never claimed to be a doctor or a medical professional and I have never told anyone what they should or shouldn’t do in regards to vaccinations," he wrote.
"I stand for the freedom to choose what goes into our bodies, I am pro-choice, pro-informed consent and pro-medical freedom. I have nothing against people who choose to vaccinate... so to label me an “anti-vaxxer” is spreading misinformation."
He went on to write he "won’t be bullied into making decisions that could impact my health and the health of my family".
Raiders veterans Sam Williams and Michael Oldfield on Thursday morning said they supported the stance of their three teammates.