A New Zealand ride-on lawnmower race erupted in violence as competitors traded punches.

A bust-up between the rivals was apparently sparked after one shunted the other about 10 metres sideways during the race, at an agricultural show in Lake Hayes, in South Island.

One of the men was pushed “beyond the point of provocation”, his boss said.

Queenstown Stihl Shop owner, Mark McLellan told stuff.co.uk that his employee was pushed into throwing about six punches after being “T-boned” by another competitor after the race.

“This guy ran over another competitor and came right up on to his deck, then clipped another competitor on the legs.

He entered a team of four mowers, obviously with the intention of winning at whatever cost.

“I’m not sure whether the chap is a wee bit mentally unstable or over-competitive, but all these incidents were just crazy things to do – especially at what was supposed to be a fun public event.”

The employee, who he declined to name, was a balanced and sensible man, who had been threatened and retaliated when he was subjected to extremely stupid actions, Mr McLellan said.

“I actually ran on to the field because there was a definite potential our guy could have been flipped and been seriously injured.

“He was on a tiny stripped-back thing and was being deliberately shunted at speed on the end of a 2-tonne machine.

“The guy driving wouldn’t stop and kept on laughing like a maniac, so our guy managed to climb up and do something that did make him stop. We’re standing by him and saying his reaction was fair.”

Eyewitness, Andrew Wallace, said had been “very entertaining and at first the crowd probably believed it was a stunt”.

“It was soon obvious it was lawn mower racing’s ugly underbelly at full clip. It was lucky the guys involved were wearing helmets.”

Greenfingers Queenstown franchise owner Dave Hunt yesterday confirmed his son Simon was the driver of the mower that shunted the Stihl Shop employee, stuff.co.uk reported.

However, he defended his son, saying Simon would not be answering his phone because of media interest.

“There was only one person throwing punches, and that wasn’t Simon,” Mr Hunt said. “The joker throwing those punches is obviously in need of a bit of anger management, because at the end of the day a little bit of a shunt is no huge deal,” he said.