The newly crowned Australian Amateur Boxing League heavyweight boxing champion defeated a far more experienced, far heavier fighter to claim his title last month.

Jonker, who went up a weight division for the fight, was unfazed about challenging the Tasmanian boxer despite the extra kilos and experience of his opponent.

"I wasn't really nervous because the people I train with are generally bigger, so it just felt like I was training," he said.

"I didn't really go in with a plan. I just wanted to hit hard. I went in with a heap of confidence and having a hard punch helps."

Ahead of the national tournament, Jonker won Victorian titles in both senior cruiser weight and senior light heavyweight divisions.

As word about his success against fully grown men spread, junior fighters became unwilling to step into the ring with Jonker.

He won the Australian cruiser weight title by default after his opponent withdrew before the bout.

Coach Nick Lundh, from Lilydale's Fight 'n' Fitness gym, said finding fights for his emerging star was becoming increasingly difficult.

He said Jonker's strength in the ring came from the fighter's discipline, focus and a strong family background in martial arts.

"He is a knockout puncher. He is very strong in his footwork and has a very strong foundation."

Lundh is hoping to get 20 fights into Jonker by the time the young boxer turns 18, at which point he will be eligible to turn professional.

Competing for a berth in the Australian team for the Delhi 2010 Commonwealth Games is also on the agenda, and Lundh and Jonker plan to travel to Thailand early next year to train further.