There he told a captive audience about the hope he discovered amid the hopelessness during his own stint inside the walls of what he called "hell".

Matagi had never played a game of rugby league when he was sentenced in 2006 to three years' prison for an assault on rival gang members in Auckland.

However, as the then 17-year-old languished in Manawatu – an adult prison – he committed himself to making his name in rugby league.

The idea he could cut it in the NRL came to Matagi after he played a prison game called "crash" – where the inmates charged into an angry defensive line and were smashed to the concrete courtyard – and he was surprised that not even the toughest blows prevented him from picking himself up to run again.

He told this to the Gatton inmates after he accepted an invitation by a welfare group to try to inspire them with his story.

"It hit me to do everything I could to play in the NRL," Matagi said.

"I thank God for giving me the hunger and the hope to do something positive with my life, and I focused my energies on making it.

"I gave up smoking, which was hard, I exercised and, when I was released, I did road runs. I knew nothing about training, I just moved. I ran up hills, built up stamina and I joined a local team."

Matagi made his first grade debut last year and represented Samoa in last year's World Cup. His odyssey from inmate to respected NRL front-rower enthralled the prisoners and, he hopes, it will also have helped them realise that, despite having a record, their lives are not over.

"I told them about my journey in life," he said. "I wanted them to understand people can come back from a setback. Your life is not over when you go to prison. We all make mistakes but you can't allow for it to be an excuse for you to stop trying.

"We all fall down but have to get up – I learned that. I believe if I get the opportunity to play for the Kiwis during the Four Nations tournament it shows to people that anything is possible if you put in the hard work and leave the criminal life behind.

"I know a lot of them reoffend and that comes from feeling no hope or having no direction. I just went there to try and inspire them. I shared my background and where I have come from and where I've started.

"Life is like a game of footy. You're going to get hit, you're going to get knocked down, but it can't hold you back.

"A lot of them spoke of feeling hopeless. I shared with them my hope and gave them the thought there is something to look forward to, so they don't reoffend and return to prison. I talked to a lot of them one on one and said it would be a struggle but they need to remember nothing comes easy, no one hands it to you on a platter."

New Zealand selection meant Matagi had to wrestle with whether to represent the Kiwis or Samoa.

"My ultimate goal was to play for the New Zealand Kiwis but I never thought it would happen," he said.

"When I first started playing after I came out of prison, I made the New Zealand residents team and played for them four years in a row. I was presented with my jersey by Benji Marshall in '09 and I remember telling myself that one day I want to be like him and become a Kiwi.

"There's been confusion about me, Samoa, the Kiwis and my decision ... playing for New Zealand, that's what my dream was but when the opportunity came it was a hard decision for me. I had to speak to my wife and family ... but this was my ultimate goal.

"I am proud of Samoa but I also looked at the bigger picture, and it is my desire to give hope to people.

"New Zealand is the highest level for me to play at. For me to get there shows the power and rewards of working hard and believing in myself. To back myself and to make the Kiwis – if they give me a game – will show anyone, be they at Gatton or Manawatu, that they can make it."