"Whanganui seems to be a pretty popular spot for it," Mr Dudley said.
The course involves a stair climb, hose hoist and stair descent, forcible entry, obstacle course and hose advance, and finishes with the victim rescue.
That's all done with firefighters fully kitted up, including in breathing apparatus.
"That's the biggest killer for most guys," qualified firefighter Glen Haden said. "Being able to manage their breathing and keeping a cool head the whole time. For a lot of the guys, it'll be their first time. Knowing the tricks of the trade is a big thing."
The best will go through the nationals in March.
Meanwhile, Mr Dudley said such events brought the firefighting "family" together. The Whanganui crew had been training with some of the Bulls volunteers. "It breaks down barriers," he said. "There's great comradeship."
The public were encouraged to check out the event in the day.
"There'll be firefighters from all over the North Island here," he said. "They call it the toughest two minutes in sport."