NSW officials have reportedly asked for an explanation from the NRL as to why Friend wasn't given a head injury assessment during the second half of the Blues' 34-10 win at ANZ Stadium.

The Maroons' hooker stayed down briefly after a collision with NSW's Nathan Brown in the 51st minute of the match and again stayed on the turf moments later after pressuring a Nathan Cleary kick.

Bennett said the reason Friend never underwent a HIA was simple, he didn't suffer a head injury in either incident.

"The doctor's not happy about it," Bennett said.

"His integrity that's being questioned here and Jake never had a head knock at any stage of the game.

"He had a shoulder from the week before. He hurt it again in the game and there was no relevance to his head whatsoever."

Concussion has been a hot topic in this year's Origin series with NSW issued with a warning by the NRL after captain Boyd Cordner was allowed to return to the field following a HIA in game one.

Cordner, who has a history of concussion issues, was subsequently ruled out for the remainder of the series.

The Maroons, who sidelined Christian Welch from game two after a head knock in the series opener, also lost playmaker Cameron Munster in the opening minutes of game two.

Maroons doctor Matt Hislop took to social media after game two to explain while Munster had passed his HIA, he wasn't allowed back to play after showing "category one" symptoms of a concussion by twice losing his balance as he attempted to get back on his feet.

Bennett, who told reporters on Tuesday that Munster was set to play game three after passing all of his concussion protocols during the week, backed Hislop and said the claim from NSW regarding Friend was a "fallacy".

"I don't care what they're (NSW) saying. I'm telling you what the situation was, he didn't get knocked out."

Australian Associated Press