"I asked a couple of soldiers what the steps were to become a referee.
"My love and passion for the game was never going to change and refereeing is a way of staying involved.
"As a sport, I love the commitment players bring to the field, the commitment their partners bring in support and the time and money they put into playing."
He got started by refereeing age-group rugby league and in 2015 he was awarded Bay of Plenty's Referee of the Year.
Kareko is now serving his second year as a referee with the Auckland Rugby League Referees Association which was "always a long-term goal".
"They have the same passion for rugby league as people in Bay of Plenty, but it's a bigger machine up there, there are so many teams.
"There's so much history there, you remember Carlaw Park days and all the history there - a history of making legends.
"Now I'm a small piece in that big jigsaw."
He is not alone on his weekly journey as his wife and one-woman support team Jacque joins him every week.
"She's really supportive and is probably the reason why I do what I do.
"She supports me in many ways and I couldn't do it without her.
"It all starts on Friday night as we get the car prepared and check the weather - if it's going to be wet we leave a bit earlier.
"We look at what games I've been appointed to officiate as well, that's a key part of our week and on Saturday we're in the car and we're gone."
He said, as a referee, his job was to give 100 per cent on the field every week.
"You're going to get criticism before you blow the whistle and you're going to get it after the game.
"You have to find a way of data dumping that criticism and you've got to do it real quick.
"My process is to believe in what I see, believe in what I see on the field and be in the right place to make a decision."
The skills he learnt in the army helped him excel as a referee.
"Commitment, camaraderie and integrity - I've been able to put that into league.
"I still get good support from the Bay of Plenty and the referees here."
His new dream was to follow in the footsteps of fellow Kiwi Henry Perenara and referee at the highest level, the Australian NRL.
"I just have to keep working hard.
"I know a lot of referees would like to make it into the NRL and I have had encouragement from New South Wales Rugby League.
"I'm committed to that goal, I'd be running around with giants of the game."