Brain Injury Australia executive officer Nick Rushworth, who prepared a paper for the federal government in 2012 that cautioned about the risk to players of staying on the field in big matches, said the Finucane incident could have been a line in the sand for rugby league's handling of concussions.

His fears the NRL's strict concussion guidelines would be twisted in the heat of a grand final were realised when a trainer, who indicated Finucane was required to undertake a sideline concussion test, did not remove the player from the field.

"The NRL has got some really good sports clinicians in place and it's times like grand finals when you think of the grassroots amateurs and the millions of eyeballs that are looking for the NRL to exercise leadership in a game like a grand final," Rushworth said.

"They can set an example for every other club right across the country for how this should be handled and, based on my understanding, it simply didn't happen.

"There is the pressure of a grand final and that kind of pressure might play out in terms of coaches, players and conditioners making decisions about whether a player can stay on or not.

"I thought it's a totally cut-and-dried policy that the player would come off the field [when a trainer taps his head]. It's my understanding that as soon as that happens there's a blanket policy of what should happen. The best practice consensus is the immediate removal of the player with concussion is recommended."

Finucane played on for five minutes after one of Melbourne's trainers indicated he needed to leave the field for a concussion test and, having taken his place back in the defensive line, he was the first to make contact with Sharks prop Andrew Fifita before he planted the ball for Cronulla's match-winning try.

Finucane was removed from the field several minutes later for a head injury assessment, triggering a free interchange.

Finucane was just one of a number of players to leave the field with head knocks during a brutal grand final with teammate Kenny Bromwich joining Sharks players Jayson Bukuya​ and Matt Prior for concussion tests.

Rushworth, who will run a concussion training day in Sydney on November 7 to examine the latest research about concussions in sport, said, given the severe danger for players to be injured from second-impact syndrome, it was imperative players be immediately taken out of the firing line.

"Whether it's a grand final or round one – regardless of the circumstances or regardless of the score – it should be adhered to," he said. "If you look at the body types of players now, as opposed to amateur days ... just think about the amount of force involved with players now who are professionals and go to the gym and are built like tanks compared to lanky ones of yesteryear."

The NRL strengthened its concussion protocols last year, but there are still fears the rules are being exploited.

Newcastle coach Nathan Brown flagged the prospect of clubs using it as a way of gaining an advantage through a free interchange by taking a player off for a head injury assessment when not suffering from concussion.

There have been calls for clubs to carry an 18th or even 19th man in their game-day squads to ensure a club that loses a player to concussion and can't return to the field isn't unfairly disadvantaged.

While independent doctors are now in place at all NRL games, the NFL has gone a step further and employed independent head injury experts and neurological consultants for sideline player assessments.

The NRL said they were still reviewing all incidents involving head knocks from the grand final.