The NRL have rebuked claims Taane Milne was incorrectly ruled out of South Sydney's loss to Canberra after a head knock, telling coaches they are not qualified to question the league's independent doctors.

Milne was deemed to have copped a category-one head knock in the Rabbitohs' loss to Canberra, and immediately ruled out of the match after showing concussion symptoms on-field.

Afterwards, Souths coach Jason Demetriou claimed he would be speaking to the NRL over the incident, adamant that there had been nothing wrong with the winger.

But at his weekly media briefing on Monday, Graham Annesley showed replays of Milne's head hitting the ground before he stumbled back to the Souths' line.

The NRL's head of football also revealed Milne had failed his off-field HIA, meaning he would not have been allowed back on the field even if he was considered a category two.

"These are player safety issues. These are not issues to be dismissed by players, coaches or anyone else," Annesley said.

"For non-medically qualified people to say he was OK or that he could have come back on the field (is wrong).

"To be brutally honest, we can't be led by opinions of non-medically trained people or by the player himself. It's a medical diagnosis that takes place."

Annesley said he had not heard from Demetriou on Monday over the situation, with the Rabbitohs also losing Tevita Tatola to a head knock.

The incident comes after coaches raised several issues over players being deemed category ones in the early stages of the season, immediately ruling them out of games.

And while Annesley admitted they had potentially been too cautious in the early rounds upon the implementation of the independent doctor, he was adamant this was not the case with Milne.

"We would be the first to admit that maybe in the opening two rounds while we settled the system down, maybe some calls made that were too safe," Annesley said.

"Maybe they went too far. But that's not the case on this incident.

"This is not a decision that has to be debated.

"It's a decision made by an independent medical practitioner who has observed signs that indicate a possible concussion.

"That decision is taken not in the best interest of the NRL… but in the best interest of the player." 

Meanwhile Annesley again defended several key calls over the weekend, including Dane Gagai's no-try in Newcastle's loss to Brisbane and the Christian Tuipulotu high hit in Manly's defeat to Parramatta.

He also remains adamant the decision to not call an obstruction before Selwyn Cobbo's try against the Knights was not a howler, and was open to interpretation as a 50-50 call.

AAP