Stuart labelled Penrith five-eighth Jaeman Salmon a "weak-gutted dog" after an incident involving hooker Tom Starling in the 26-6 loss to the Panthers.

The personal gripe stems from a clash between the the two and Stuart's son in Sydney they were playing in the same junior team at Cronulla.

Stuart is still incensed by what happened, but declined to shed more light on the situation when asked by The Canberra Times and then apologised for his actions on Sunday.

The Raiders say it is now a matter for the NRL, with league bosses launching an investigation before deciding what punishment, if any, they will hand Stuart.

In a statement on Sunday morning, Stuart apologised for the verbal attack and conceded his emotions got the better of him.

"I regret saying what I did on that platform after the game," Stuart said in a statement.

"I was speaking as a father and not as a football coach.

"My reaction was to a family situation that I thought I had dealt with, clearly I haven't.

"I allowed my emotions to get the better of me and for that I am very sorry.

"There is a history between Jaeman Salmon and my family that I will not go into.

"I should not have brought it up after the game, but it just got the better of me.

"I am truly sorry that I have caused my family and the game unwarranted attention."

The comments prompted an immediate firestorm, many fans and commentators quick to condemn the Raiders coach.

Talking on the Sunday Footy Show, NSW Origin coach Brad Fittler identified the stress Stuart would currently be under, the Raiders mentor attempting to lead his side into the top eight.

With Canberra producing an underwhelming performance against a depleted Panthers side, Fittler said Stuart's emotions boiled over.

"It shows the level of pressure coaches and clubs are under fighting to get into the eight," Fittler said.

"They're in a tough position at the moment, they need to win. They were pretty unconvincing against the Panthers.

"We all agree, including Ricky, that wasn't the place. It's where parenting got in the road of being a professional coach."

Salmon was asked if he wanted to respond and defend himself on Saturday night, but the Panthers advised him not to add further comment.

Salmon's Penrith halves partner Sean O'Sullivan told the Sunday Footy Show the five-eighth was rattled by Stuart's remarks.

"We spoke to Jaeman after the game, I think he was a little bit rattled by it," O'Sullivan said.

"We all know the type of person that Jaeman is, we love him on and off the field.

"Everyone in the organisation will be supporting him, he's a good person, I'm sure he won't be too worried about what someone externally says."

For Darren Lockyer, that highlights the most disappointing aspect of the situation, both parties feeling the negative fallout from the comments.

"He's come out and said he's made an error in judgment in airing that personal frustration on the platform," Lockyer said.

"No one wins out of this. We don't know the history of it all, but obviously it's hurt him deeply. Unfortunately he's aired that on the wrong platform."

NRL chief executive Andrew Abdo was among those disappointed by the remarks.

Talking on radio Sunday morning, the league boss declared a full and thorough investigation would be conducted in the coming days.

"Whenever there's an issue like this, we ask the integrity team to gather information and have a look at it," Abdo told Sky Sports Radio.

"Obviously as a decisionmaker, I also need to involve myself and speak to the respective parties as well.

"Clearly, the comments are disappointing and we're going to take a close look at it. It has just happened, so everyone deserves due process.

"We'll engage with Ricky, understand all the facts, gather all the information then deal with it through the course of the early part of this coming week, as we do with everyone that happens of the round."

Stuart was discussing a controversial incident during the match in which Salmon appeared to lash out at Starling.

Salmon's boots made contact with the hooker's head and groin region, the Canberra coach labelling it a deliberate act.

The Panther was penalised and placed on report after the incident.

"He's got the double whammy. One in the lunchbox and one on the chin," Fox Sports commentator and former NRL player Michael Ennis said of the incident.

When asked about the incident after the match, Stuart did not mince words in describing his thoughts.

"Where Salmon kicked Tommy - it ain't on," Stuart said in his press conference.

"I've had history with that kid. I know that kid very well. He was a weak-gutted dog as a kid and he hasn't changed now.

"He's a weak-gutted dog person now."

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Ivan Cleary was unaware of what Stuart had said until asked about it in his press conference.

"I don't think I need to respond to those comments," Cleary said. "I know what Jaeman is like and he's valuable at our club, and we love him.

"It's hard to see with the small screens. I can't imagine Jaeman would have deliberately done that. I honestly didn't really see it."

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