Gold Coast Titans, St George Illawarra Dragons and Newcastle Knights each face hefty fines after being landed with concussion breach notices from the NRL.
The proposed fines - which NRL chief executive Todd Greenberg said were the biggest in the competition's history - total 350,000 Australian dollars and follow alleged failures to follow concussion protocols during third-round matches at the weekend.
The Titans face the biggest fine (150,000 AUD) for incidents involving Kane Elgey, Joe Greenwood and Ryan Simpkins, while the Dragons and the Knights each face penalties of 100,000 AUD for incidents relating to Josh Dugan and Brendan Elliot respectively.
Greenberg said: "These are, by far, the heaviest fines ever proposed by the game for concussion breaches. That is how seriously we take it.
"The clubs involved have the opportunity to respond to the breach notices and we will consider those responses, but our message is clear: we are not going to allow player safety to be put at risk through breaches of the concussion rules."
Each of the clubs has five working days to respond to the notices.