Since then they haven't looked back, practising once a week in Mr Corbett's garage for about six hours at a time.
They said they were invited to compete at the 2013 FitX Sport and Fitness Expo in Melbourne, held this month, after winning New Zealand titles in Auckland.
"I thought Maat was a big guy but some of the guys over there, man, they were huge as," Mr Corbett said.
"But we were really happy with our results."
Mr Heta-Morris said the atmosphere was brilliant.
"It was really professional, I have never been to one like that. We must have been the most inexperienced guys there," Mr Heta-Morris said.
The greatest arm wrestler of all-time, John Brzenk, who featured in a Sylvester Stallone arm-wrestling film, made a guest appearance at the tournament.
The pair are now looking to create a New Zealand arm-wrestling federation, which would make them eligible to compete at the world champs in Poland during September.
To watch a video of their arm-wrestling competitions or to sponsor the pair, visit their Facebook page - Brothers in Arms Rotorua Armwrestling.