Newcastle are also facing a $100,000 fine after allowing young fullback Brendan Elliot to play on despite clearly being wobbled in the Knights 24-18 loss to Souths on Saturday while Gold Coast were fined $150,000 for their handling of three separate incidents in their win over Parramatta on Friday.

Read more: Dragons doctor couldn’t access vision of Dugan incident

The Dragons attracted scrutiny after Josh Dugan was left prone on the turf after being leveled in some friendly fire from Russell Packer in the ninth minute of Sunday’s clash with Cronulla.

Dugan stayed down for almost a minute while he was assessed by head trainer Nathan Pickworth but remained on the field and played out the remaining 71 minutes without undergoing a Head Injury Assessment.

Read more: Will the real St George Illawarra Dragons please stand up

Coach Paul McGregor backed his medical staff post-match, saying the report he received was of a potential jaw injury and not a concussion.

“It was a jaw injury, not a head injury. That was the report I got back in the box,” McGregor said.

“I had [utility back] Kurt Mann there so I had a bloke I could put on straight away but they said it was his jaw and I’ll back the medical staff there. If it’s a jaw it’s jaw, nothing to do with concussion.”

The Knights copped a barrage of criticism for their handling of Elliot who was knocked senseless by a 28^th minute tackle from Hymel Hunt that saw the Rabbitohs centre hit with a grade two reckless high tackle charge. Elliot eventually underwent an HIA after copping a second knock in the 62^nd minute of the match and didn’t return with coach Nathan Brown taking aim at the NRL’s concussion replacement rules in the aftermath.

The Gold Coast’s fine relates to their handling of three different incidents involving Kane Elgey, Joe Greenwood and Ryan Simpkins in their win over Parramatta on Saturday night.

All three clubs, two of which are currently owned by the NRL, have five days to respond the hefty breach notices but chief executive Todd Greenberg said the unprecedented sanctions send a clear message.

“These are, by far, the heaviest fines ever proposed by the game for concussion breaches. That is how seriously we take it,” Greenberg said.

“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.”

The NRL first introduced new protocols for the handling of concussion in 2012 and has beefed them up in ensuing seasons. Greenberg said that while most clubs have adhered to the guidelines, the incidents in round three clearly did not.

"I watched [Sunday] night's game on the lounge with my family and I was dismayed Josh Dugan wasn't taken off for assessment," Greenberg said.

"The reality is I don't know if it was a concussion - and nor does anybody else - but that's not the point. The point is our rules are very clear if a player lies motionless on the field he must come off for an assessment. That didn't happen [on Sunday night] and that's not good enough.”

The sanctions come as former Newcastle and NSW State of Origin winger James McManus begins legal action against the Knights, alleging the club mismanaged the multiple concussions that ultimately brought a premature end to his career. 

In a statement released by the Dragons late Monday, the club said it was yet to formally receive the breach notice but stated that the club has:  “the upmost respect for player safety and fully support the NRL’s rules and processes in relation to concussion, as our track record would support.

“Equally, the Dragons support the integrity of our medical staff in their decisions and delivery of the NRL's procedures and policies. The club will await the formal breach notice details and will make no further comment until this process is complete.”