NRL referees boss Bernard Sutton has contacted a "filthy" Gold Coast Titans coach Garth Brennan to say play should have been stopped when hooker Mitch Rein went down with a suspected neck injury in the club's 35-12 loss to the Penrith Panthers on Sunday.

Rein was complaining of pins and needles down his arm just before half-time while being attended to by Gold Coast trainer Craig Catterick, an experienced nurse, who was wearing an orange shirt.

Club officials that wear orange shirts in such a role must be qualified doctors, physiotherapists, nurses or paramedics.

Catterick shouted to match officials to stop the game but they did not heed his call. The Panthers scored for a 10-6 lead while Rein was still on the ground being attended to.

"I have spoken to Garth Brennan and advised him that play should have been stopped under the circumstances," Sutton told NRL.com.

"There is a level of discretion which the match officials can apply to certain scenarios, based on the seriousness of the injury as well as where it occurs on the field.

"If an injury is serious, a team can request that play be stopped through the sideline officials so that a doctor can enter the field of play.

"In this case, the message was relayed to the touch judge, and play should have been stopped as a result."

Brennan stressed he was not blaming the match officials for his side's loss but said player welfare and consistency was paramount in such a situation.

"I'm filthy that they didn't stop play when Mitch Rein went down and my biggest concern is duty of care to our players and the inconsistency with it," Brennan told NRL.com.

"The play went on for three or four tackles and he was down in the back-play with a suspected neck injury.

"A rule came in not long ago where the orange shirts had to have suitable qualifications so they could make informed decisions about injuries in the game.

"Craig Catterick is an experienced orange shirt and been in the game a long time and worked with the Australian side. He's very thorough in what he does.

"He is indicating to the referees to stop the play. Luke Burt, my assistant coach in a blue shirt, was screaming at the touch judge to stop the play.

"Then the referees and touch judge say it is at their discretion to stop the play. Are referees and touch judges medical experts now?"

Brennan said play was often stopped when players had cramps, a fatigue injury, and reiterated that Catterick had his player's best interests at heart when he made his call.

"Mitch Rein was saying 'get me up so I can get back in the line' but we don't want players getting back in the line with serious neck injuries because match officials think they are doctors," Brennan said.

"Craig was restraining Mitch and assessing whether he had a neck injury, and fortunately he didn't, but this week there will be players with cramping and the referee won't restart play until they are attended to.

"There is a duty of care to our players and I thought they were negligent in that they didn't stop the play.

"Did it cost us the game? No it didn't, but Penrith scored while Mitch was down and went in at 10-6 up instead of 6-4 down."

Brennan was proud of his side's performance considering his captain Ryan James was suspended, lock Jai Arrow (back spasms) didn't finish the game, Nathan Peats (rib) left the field in the 26th minute, while Dale Copley (hamstring) exited late in the game.

Morgan Boyle also was ruled out in the warm-up after colliding with Bryce Cartwright and will face head injury protocols before being cleared for the clash with the Cowboys in Townsville on Saturday night. Brennan said Peats and Copley were both out of the game against North Queensland.