Gagai, the 33-year-old former Kangaroos and Queensland Origin representative, is off contract at the end of this season but has no intention of retiring.

Instead he hopes to re-sign with the Knights for another two or three seasons and kicked off his retention campaign with a standout performance in last week's season-opening loss to Canberra, in which he gained a game-high 210 metres in attack and made 14 tackles, with no misses, despite being hindered by a chest infection.

Gagai told the Newcastle Herald that he has unfinished business because he wants to cap off an outstanding career that has delivered 22 Origin appearances and seven Tests with a premiership triumph.

"I'm definitely not thinking this'll be my last year," Gagai said.

"I'm not quite done yet. I still want to win a grand final."

After debuting for Brisbane in 2011, the Mackay product has strung together 269 NRL games for the Broncos, South Sydney and, in two stints, Newcastle.

He sees no reason why he can't emulate the likes of Cameron Smith, Paul Gallen and Daly Cherry-Evans by playing into his mid-30s, pointing out that he has managed to avoid serious injuries during his 14-season career.

"The body's feeling good and I'm looking to go another two or three years," Gagai said.

"I've been very fortunate. I've never really had any major surgeries.

"The biggest one I've ever had was a cleanout of a dislocated pinky [finger].

"So I'm still feeling fit, feeling strong.

"I've always said that once I can't keep up, or I lose the passion for it, that's probably the day I look at retirement.

"But that's still a long way away.

"I'm looking to go another couple of years after this, but my main focus is this year.

"I've always believed that that stuff sorts itself out.

"For now, I'm just focused on this season and trying to build on last year and hopefully making the top four.

"We know how important that is if we want to win a premiership."

Whether Gagai can continue playing as long as his father Ray did remains to be seen.

"Dad was 40 when he finished up in Mackay, still playing A grade," Gagai said.

"So I'm not sure if it's the Torres Strait Islander genes, if I've got good ligaments, or what it is.

"But Dad didn't have many injuries, and I've been very fortunate in my career to avoid them. Touch wood."

Gagai has also not given up hope of winning an Origin recall.

After helping the Maroons win five of the eight interstate series between 2015 and 2022, Gagai was overlooked last season in favour of Hamiso Tabuai-Fidau.

The Dolphins flyer proceeded to score four tries across three games as Queensland retained their title.

Maroons coach Billy Slater, however, has clearly not shut the door on Gagai, inviting him to attend a pre-season Queensland bonding weekend recently.

"Obviously that was one of the tougher times in my career, probably more so because I've got an eight-year-old son now and all he's ever known is me playing rep footy," Gagai said of last year's omission.

"I obviously took it hard, but I think he took it ever harder, and that doubled down on it for me.

"I haven't given up on Origin.

"I still love the state and will do whatever I can for them, but like I said, it's a new year and my focus is on Newcastle and I'll be doing everything I can to win enough games to hopefully make the top four.

"All the other stuff will take care of itself."