It has been revealed that cases where NRL clubs are fined for breaches of concussion rules could be kept secret from the public.

Last year three clubs — the Knights, Dragons and Titans — were issued breach notices and fines totalling $350,000 because they failed to remove players for head injury assessments despite those players exhibiting signs of concussion.

NRL chief Todd Greenberg said at the time: "I watched last night's game on the lounge with my family and I was dismayed".

The NRL fined the Titans $150,000 with $100,000 suspended.

The Dragons and Knights were each fined $100,000 with half the amount suspended.

But the code will now decide which cases will be made public.

"We will always treat concussion-related matters on a case-by-case basis, as we would any other issues arising out of the NRL rules," an NRL spokesperson said.

"Some will be in the public interest to disclose, while others will be dealt with privately with clubs.

"We are committed to enforcing our concussion and head injury rules. We have demonstrated that in recent years and that work will continue."

Roosters captain Boyd Cordner (pictured playing in 2017) returned to the field after being assessed for a head injury in Round 4 against the Warriors. ( AAP: David Moir )

Last month the NRL asked the Roosters to explain their use of a free interchange after Boyd Cordner returned to the field after undergoing a head injury assessment.

The club has confirmed no fine was issued.

The NRL also quizzed the Sharks regarding a lack of action when Josh Dugan appeared to have a bad head knock during their round two match against the Dragons.

The Sharks said they did receive a breach notice for the incident but have appealed against it.

The NRL's chief medical officer Dr Paul Bloomfield said clubs are taking concussion seriously.

Josh Dugan was also concussed in 2017 when playing for his old club, the St George Illawarra Dragons. ( AAP: Dan Himbrechts )

"Attitudes towards that are definitely improving and I think clubs as a whole are being more conservative with their management in game of concussions and it's reflected in our reviews of concussions and discussions with club doctors," Dr Bloomfield said.

The AFL has told the ABC any fine in its code, including a concussion breach over $2,000 would be made public.

The NRL has also revealed from next season it will be compulsory for all 16 NRL clubs to have two doctors at the field during a game.

"The clubs next year will have an assistant doctor, so two doctors per club," Dr Bloomfield said.

"If a doctor is inside, there's still another doctor on the sideline and also because it [concussion] is still a difficult and complex thing.

"The team doctor will then still have the opportunity to discuss it with someone who also knows the players, and as [they say in the] US … it's the co-pilot/pilot scenario.

"So you have the pilot and the co-pilot and if the pilot wants a second opinion they've got someone there ready."

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Breaches should be public, says AMA

But the Australian Medical Association (AMA) disagrees with the sporting bodies. AMA professor Brad Frankum said concussion breaches by NRL clubs should be made public.

"I do think breaches should be subject to public scrutiny in order to pressure clubs to do the right thing," he said.

"Concussion breaches are serious and endanger player health. There are likely multiple reasons why they occur, but if it is deliberate by player or coaching staff, that is a practice that must be severely penalised.

"Doctors in all situations are ethically bound to do the right thing medically for the individual for whom they are responsible, so team doctors must not be pressured in any way when they are making clinical decisions.

"I can't really see that the publication of breaches will affect a doctors reputation away from the football field if they have made decisions ethically and with their best judgement."