In his newly released autobiography Heart And Soul, the former Test and Origin warhorse refers to Newcastle's 2016 wooden spooners - who won only one game all season - as "the worst first-grade team I ever faced in my entire career".

"I remember playing for Australia against minnow teams such as the United States, and the Knights were even worse than them," Gallen wrote, adding that he "felt sorry for the Newcastle players and fans" after Cronulla's 62-0 slaughter of the Knights at Hunter Stadium in round 10, 2016.

"I only played about 30 minutes in our huge win over Newcastle, as my knee was still giving me grief ... from the sidelines I could see that, although the opposition was vastly inferior, we showed little mercy," he recalled.

"As I said, I felt sorry for the Newcastle boys that day. After the game, I walked onto the field to shake hands, and it felt like I was grabbing the hands of kids.

"I didn't even know most of their names. It wasn't their fault."

Gallen said he was worried that the repeated thrashings Newcastle suffered in 2016 would "scar" promising rookies like the Saifiti twins, Daniel and Jacob.

"Losing becomes a habit, and I desperately hoped the repeated pummelling they were receiving wouldn't leave them questioning their motivation," he wrote.

Gallen said he gave the young Knights "huge credit" for fighting back to win five games the following season, when they collected a third straight wooden spoon.

On a number of occasions in recent years Gallen has offered disparaging opinions about the Knights, in particular when Mitchell Pearce signed for Newcastle, not Cronulla, after leaving the Roosters at the end of 2017.

On that occasion, Gallen declared in a website column the halfback "might live to regret" his decision because "Newcastle are two or three years away from being a consistent top eight side".

"As for winning competitions, well, I just can't see that happening for a long, long time," he added.