After missing the birth of his son just to train with New South Wales, Blues debutant Mitch Barnett feels he has no choice but to make the most of his shot at State of Origin.

The Warriors forward was a member of the Blues' extended squad for Game I and II but missed the delivery of his son Zane, who was born six days before this year's Origin opener.

Barnett made a rapid-fire trip across the Tasman to be with his wife Clare and newborn son but not before completing his duties with the New South Wales squad.

"I had to leave camp to get back for the birth but I missed it. It was planned, but I had an obligation to help the boys — I trained here and got on a flight knowing I'd miss it," Barnett said.

"It was an opportunity and I had to be here, it was my first time being selected in the group. It'll make for a great story one day.

"I wasn't the only one who sacrificed stuff, all the boys sacrificed things. The fans probably don't see what NRL players do on a daily basis in terms of sacrifice, they move away from family and all that sort of thing, but it's a short career and you have to make the most of it."

Barnett spent part of his first day as an official Origin debutant organising a passport for Zane, with the family planning for the newborn and his two-year-old brother, Nate, to be on hand for their father's Origin debut at Lang Park next Wednesday.

The 30-year-old's commitment to the Origin cause no doubt helped him land a bench spot for the decider, with Barnett making a point of doing all he could to help the side in the lead-up to the first two matches.

"[I focused on] being the best teammate possible. Whatever anyone needed, I was ready to do," Barnett said.

"That's something I live by, being the best teammate possible, whether that's playing or not playing. It was a new role for me but I just wanted to do everything I could to win."

That's the attitude that has Barnett playing career-best football at the Warriors, a process that began after he made the difficult decision to leave Newcastle for New Zealand two years ago.

Barnett was a solid performer during his seven years with the Knights but has taken his game to another level under Warriors coach Andrew Webster.

Even during the club's inconsistent 2024 campaign, Barnett's form has never wavered and the aggression he sometimes struggled to contain at the Knights has been controlled and channelled.

"A lot has changed. I got out of my comfort zone in Newcastle and moved to New Zealand, that's the biggest one," Barnett said.