The NRL said today it would not tolerate any abuse of junior match officials, following serious allegations involving two Cronulla Sharks players.

CEO Dave Smith said match officials are the lifeblood of the game and there will be serious consequences for any NRL players engaging in physical or verbal abuse or intimidation of them.

"Match officials give up their time because they love the game and the last thing they should be subjected to is abuse or intimidation," Mr Smith said.

"It is even more intolerable if someone with the stature of an NRL player is involved -  we want the full facts to be presented in this matter."

Mr Smith said there had been mixed messages today in media interviews as to whether either of the Fifita brothers had admitted  directing foul language towards a match official.

The Integrity Unit had therefore written to the Sharks advising that, if either player has admitted abusing a match official, they should be stood down from today's game.

"The NRL will never prejudge anyone accused of breaches – everyone is entitled to the presumption of innocence," Mr Smith said.

"But if we become aware of any NRL players abusing match officials there will be very significant consequences."