The Queensland Rugby League have been fined a staggering $30,000 for their interchange breach during Game 1.

Penalised on the field at the time for having 14 players on the park, the incident occured when the Maroons attempted to remove an injured Tom Gilbert from the field and replace him with Lindsay Collins.

Gilbert, who was taken off the field on the far side of the ground away from the interchange benches by Queensland officials, didn't leave the Dolphins' forward quickly enough though.

So obvious was the breach, referee Ashley Klein was able to penalise the Maroons in a rarely used piece of refereeing.

The NRL have on Friday afternoon handed down a $30,000 in a breach notice.

"The National Rugby League (NRL) has today issued the Queensland Rugby League with a breach notice following events that occurred during the State of Origin match on 31 May 2023," The NRL wrote in a statement.

"The Breach Notice proposes a fine in the amount of $30,000 for an alleged breach of the NRL Operations Manual.

"Approximately 18 minutes into the match, the Maroons had 14 players on the field for approximately 30 seconds.

"The alleged breach occurred following an injury to Maroons player Tom Gilbert. Maroons Player Lindsay Collins entered the field of play to replace Player Gilbert, however Player Gilbert failed to leave the field of play resulting in both players being on the field at the same time.

"The referee noticed the Maroons had 14 players on field and awarded a penalty to the Blues.

"The QRL has 5 business days to respond to the notice."

It comes after coach Billy Slater explained the incident in the post-game press conference.

"There was a couple of seconds that we had 14 players," Slater said.

"I thought Tom Gilbert had been taken off on the other side. His shoulder popped out so he was in a pretty bad way, so we made that call to get Lindsay on thinking Gilbert was off the field on the other side."

Gilbert has suffered a dislocated shoulder and could be ruled out for a number of weeks, although the Cowboys are yet to provide official word.