Three Canterbury Bulldogs players are under police investigation following the club's raucous Mad Monday session

The NRL has issued the club with a breach notice proposing it be fined 272-thousand dollars, after players were photographed intoxicated, vomiting, passed out and naked at a Sydney hotel.

NRL CEO Todd Greenberg says the proposed penalty has been influenced by the fact the club organised the event, and failed to take the simplest of measures to ensure it was conducted appropriately.

He says the actions of some players and officials were inexcusable and the NRL is determined to send a message that it will not be tolerated on this occasion, or in the future.

The Bulldogs have five business days to respond.