Manly have been hit with a $25,000 fine from the NRL after Des Hasler questioned referee Ben Cummins' officiating in last Friday's 22-20 loss to Parramatta.
Hasler claimed the Eels were given a leg-up by Cummins and said the referee needed to review his own performance after the Sea Eagles were on the wrong end of a 9-2 penalty count.
Manly prop Josh Aloiai also criticised Cummins' performance and intimated the referee had unfairly penalised Hasler's side.
NRL chief executive Andrew Abdo labelled Hasler's comments as "disappointing" after issuing the Sea Eagles with a breach notice on Friday.
"We understand that passions run high, but that is simply no excuse to make comments which question the integrity and competence of our officials," he said.
"Public criticism of this nature makes it harder to recruit and retain match officials at all levels of the game.
"To see not only a coach, but a player, criticise officials to this extent is not the level of professionalism we expect in rugby league."
Manly have until next Friday to respond to the breach notice.
