A convicted armed robber was allowed out of a New South Wales prison to help his team win a rugby league grand final.

Acura "Junior" Niuqila, 32, took the field for the Redfern All Blacks as they defeated the Coogee Randwick Wombats to take out the South Sydney District Junior Rugby League competition.

Niuqila is a minimum security prisoner from Long Bay Jail who has two years to serve for a conviction for conspiracy to commit an armed robbery.

Three times a week he is allowed out, under guard, to train or play rugby league through a day release program.

He tells young people and his team mates: "Crime doesn't pay. All you get is sadness".

Niuqila told the ABC the was convicted because he became close to a bad crowd.

"There was no role model for me. I felt the most comfort with my mates on the street," he said.

The former Australian Rugby Sevens representative was used a number of times during his team's 28-16 win.

But Niuqila's celebrations were cut short, as he returned to Long Bay straight after the match.

"Being in a community gives you a high, back then it is back through the walls, back in the cage," he said.

"My grand final celebration will be in 2018. So I will have a beer with them then."

Niuqila's prison guard Peter Shiraz said the one-time sevens star has to stay within his sight at all times.

"Junior knows if he is not in my sight, he is in the wrong place," Mr Shiraz said.

"So wherever I look, Junior is there. He is good at that."

The program is designed to prepare inmates for release into the community.

Long Bay Correctional Complex general manager Pat Aboud said the program had taught Niquila team work and resilience.

"It gives him those skills, so when he gets out he's part of a team, he's part of a community," Mr Aboud said.

Looking on at the match was NSW Governor David Hurley, who has backed the program.

"They've made some stupid mistakes, but this gives them a real opportunity to get back into the community to show they have changed their ways," he said.