Referees have been instructed to penalise players for deliberately passing the ball into defending players at the ruck.

All NRL Clubs have been informed of the directive, which will come into effect from Round 12 onwards.

Referees will now rule that if a dummy half deliberately passes the ball into a defending player caught in and around the ruck who is not actively taking part in the play, the act will be deemed to be contrary to the true spirit of the game. A penalty will be awarded against the attacking team.

"What we have seen recently is a bad look for the game, and in simple terms, not in the spirit of the game," NRL Head of Football Brian Canavan said.

"In these instances, if a player deliberately throws the ball into another, the referees will give a penalty to the opposition team.

"This does not absolve a defender of his responsibilities to clear the ruck and the defending team will still be penalised if it is deemed that they are interfering with play."

Mr Canavan also said referees had been instructed to communicate warnings or cautions for repeated infringements to Captains more efficiently in order to minimise delays in restarting play.