The NRL admitted a touch judge had made a crucial error in the lead-up to a Sharks' try midway through the second half, raising his flag before the referee put the whistle to his mouth but allowed play to continue.

The frustrated Raiders refused to blame their crucial loss on the decision, but Stuart took aim at the NRL over bigger issues he claimed had led to fans turning away from the sport in 2018.

"All this rot started at round one this year," Stuart said.

"I don't know who came out and told the referees they had to come in and pick on everything ... start nitpicking on shitty pieces of play.

"This is why people are turning off rugby league. It's sad. I don't blame the referees, they've got a tough job, but too many voices around them are making it too hard for them."

Stuart took particular exception to an email from NRL officials this week, which it's believed told coaches players would be penalised for deliberately slowing down the play-the-ball after an increase in the tactic.

"We've ruined the first 14 rounds of the competition, we've lost fans and I know people who have turned off because of it," Stuart said.

"But then halfway through the year (NRL CEO) Todd (Greenberg) comes out and says I've told the referees to stop nitpicking.

"We're the only sport in the world that changes interpretations midway through the year.

"All the head coaches get an email this week telling us that this won't be acceptable this week. I had one session after that. What am I meant to tell the players?

"It's like a cricket umpire saying lbw this week is only going to be leg stump and middle stump."

The Raiders coach also attacked the NRL's bunker, accusing it of ruining momentum in play and making it harder for referees.

He also questioned what his players were meant to do in Friday's loss, when touch judge Rick MacFarlane incorrectly raised his flag following an apparent knock on in the lead-up to a try.

Australian Associated Press