The Broncos cannot make a signing announcement until the end of the cooling off period.

Bird will join Brisbane on a four-year $4 million deal.

The Sharks released a statement confirming Bird would depart which angered the Broncos.

"Our club has today been advised that regardless of our best efforts to retain him, Jack Bird has accepted a multi-year contract at the Brisbane Broncos," the Sharks statement said.

"Despite our club making its highest ever financial offer to secure a current player, it could not match the multimillion-dollar deal offered to Bird to join the Broncos."

It  prompted the governing body to send an email to clubs reiterating the rules surrounding the announcement of player signings.

"The rule prohibiting the announcement of any signing until the cooling off period has expired only applies to the team signing a new player," an NRL spokesperson said.

"So the Sharks have not broken an NRL rule. However the NRL will be writing to clubs reminding them of the right protocols in relation to signing or releasing a player."