The NRL's head of football Graham Annesley has promised to shut a loophole in the captain's challenge which allowed the South Sydney Rabbitohs a challenge in Friday night's clash with the Penrith Panthers which they weren't entitled to.

Under the current rules regarding the captain's challenge, teams are only allowed to make a challenge when there is a stoppage in play.

The Rabbitohs, however, gave away an intentional penalty during their clash with the Panthers to have an earlier play on call referred.

As it was in the same play as the penalty, where a Penrith player had appeared to knock the ball, referee Ashley Klein allowed the challenge to stand.

At his weekly footy briefing, Annesley confirmed that it wasn't a legitimate challenge.

“That’s not a legitimate challenge because it’s not (challenging) the decision that the referee made. The referee made a ‘play-on decision’, which can’t be challenged,” Annesley explained.

“Some people will say, ‘Does it really matter, as long as we get the decision right?’

“But there has to be some parameters around this.

“If it doesn’t have parameters around it, we’re stopping the play all the time.

“We have to try and find that right balance between correct decisions and the intrusion that technology can have on the flow and continuity of the game.”

Already this week, Australian Rugby League Commission chairman Peter V'Landys has revealed teams will penalised heavily if the wrestling isn't taken out of the game in the coming weeks, with referees instructed to go back to calling more six agains.

Annesley's comments are another bain on the game being slowed down, with the example referred to seeing Rabbitohs hooker Damien Cook laying all over a Penrith tackle inside his own 40-metre zone before a penalty was eventually given to Penrith, only for it to be reversed into am knock on by the bunker after the challenge.

Annesley confirmed players could be sin binned for intentionally giving away penalties, while also admitting there had been inconsistency in the rule.

“If he thinks that a player is using gamesmanship, for example, to slow the game down … then the referee still has the ability to take action on that (by sin-binning the player),” Annesley said.

“It’s a high-risk strategy just to try and get a decision reviewed, which you may or may not get right anyway.

“There’s been a bit of inconsistency in the way the referees have reacted,”