Graham Annesley has turned the blowtorch back on NRL clubs after a chorus of coaches - led by Canberra's Ricky Stuart - criticised the independent doctor for being overly conservative in ordering players off for concussion checks.

Stuart, along with Dolphins coach Wayne Bennett, Canterbury's Cameron Ciraldo and Newcastle boss Adam O'Brien voiced concerns during round one that the independent doctor was overly sensitive in ordering players off for head injury assessments (HIA).

Independent doctors monitor a multitude of TV angles for signs of concussion and can inform the on-field referee to halt play and send a player off for a HIA.

The system, which was introduced last year, allows club doctors to tend to injured players while ensuring that no potential concussions go unsighted.

But NRL head of football Annesley was quick to remind the game's coaches that it was because of them crying foul that the system was brought in.

"The clubs were screaming for us to introduce independent doctors (partly) because the clubs don't trust each other," Annesley said.

"There were all sorts of claims that they (clubs) are rorting the (HIA) system."

Annesley made no apologies for the independent doctor being overly cautious.

"Do they maybe today err on the side of being conservative? Maybe," he said.

"Wouldn't we all rather err on the side of being conservative when it comes to the health of a player than being too liberal?

"(If a player) stays on the field and gets another knock, a more serious one which could compound it.

"That can have long-term implications for the player, we've seen too many players retire early due to head injuries."

Annesley said only five of the 19 HIAs over round one were initiated by the independent doctor.

Among those was an incident involving Canterbury winger Jacob Kiraz, who was rocked back in a tackle in the 29th minute of his side's 31-6 loss to Manly on Saturday.

While he was off the field, the Bulldogs backline was out of whack and their woes were compounded when Manly hit the lead after Kyle Flanagan was sin-binned.

"I may have got whiplash, but I was fine after it," said Kiraz, who was later cleared and returned to the field.

"I got confused when the physio told me I had to get off.

"Obviously I know their intentions aren't bad and they don't want me to get out of the game, but at the time it was a crucial moment.

"After their careers, a lot of players are suffering from that so I understand the intentions."