Brisbane coach Wayne Bennett is standing firm behind his criticism of Cronulla, sarcastically claiming that former Sharks star Jack Bird must have injured his shoulder while falling out of bed.

The Broncos splashed out $3.5 million to lure Bird their way on a four-year deal, but will be without their star recruit for the opening rounds of the 2018 NRL season after he was forced to undergo a shoulder reconstruction.

Bennett accused Cronulla of not passing on any medical information, and claimed the Sharks told Brisbane that Bird's 2017 end-of-season scan results indicated he did not require an operation for his chronic shoulder problem.

But Bennett said when Bird underwent more scans at the Broncos, it was clear surgery was needed.

The Sharks hit back at those accusations, saying: "The comments made with regards to the Sharks sweeping a player's injury under the carpet are misleading and false."

Bennett brushed aside Cronulla's claims of innocence, and couldn't help but have a sarcastic dig at the Sharks.

"He didn't play any more football after they gave him the clearance," Bennett said of the 22-year-old.

"I'm not sure whether he fell out of bed or not. Maybe that's what happened.

"What I said in the first place - nothing has changed.

"Jack's had the operation and it's much more serious than they thought."

The Sharks said Jack underwent the standard exit medical assessment with the club's medical staff on September 14.

They deemed surgery was not necessary.

Bird then carried the injury into the Prime Minister's XIII annual fixture in Papua New Guinea - while he was still under contract with the Sharks.

"As Jack competed, we assume that the Australian medical staff deemed Jack fit to play," the Sharks said.

The war of words has set the scene for a fiery round 15 Cronulla-Brisbane clash at Shark Park next year.