The NRL has altered its stance on allowing the bunker to rule on live play, with video referees to call for penalties that are now "likely" to draw charges from the match review committee.

Just two weeks after coaches recommended the bunker be curtailed of its powers, referees boss Tony Archer reacted to his officials missing St George Illawarra forward Joel Thompson's high shot on Thursday.

Thompson will miss one game after taking the early guilty plea for a swinging arm on Canberra five-eighth Blake Austin that broke his nose, and also went unnoticed by the on-field referees.

A confused Raiders coach Ricky Stuart questioned whether he had missed a memo from league headquarters.

Archer said his men simply missed the penalty.

"The bunker reviewed the incident, (but) for the bunker to be involved in foul play, they need to be satisfied that it's more likely the person will be charged," Archer told the NRL website.

"They have to make that assessment in real time, unlike the match review committee who have time to process it in more detail. In those circumstances, we elected to play on.

"But it should've been given a penalty on-field."

The central command centre had seemingly been stripped of its powers following a coaches meeting a fortnight ago where they agreed on the on-field officials be left in charge of foul play.

Previously, video referees could get involved for "reportable offences", however Archer claimed that the rule had never been properly defined.

"We now want them to be satisfied that it's more likely the person will be charged," he said.

"They're looking at it in those details now, so until we get back before the competitions committee, we'll stick with this."

In good news for Canberra, Archer praised his officials for calling the first ever penalty for a wall, just one round after the Raiders should've got the same call in a last-minute loss to Penrith.

"Obviously a couple of weeks ago we related to one that we didn't rule correctly out of the Penrith-Canberra game," Archer said.

"But the action of the St George players, where they lined up side by side next to the play the ball and impeded the defender from having a direct line at the player in possession, that's a penalty."