In August last year Mr Holmes' employer was issued a notice prohibiting the carrying of passengers on quad bikes and requiring the use of helmets.
Holmes was supplied with a copy of that notice, but on October 3, last year he was again spotted carrying a child on a quad bike. Neither he nor the child were wearing a helmet.
WorkSafe NZ's general manager of Health and Safety Operations, Ona de Rooy, said Holmes put his own life, and the life of the children he carried as passengers, needlessly at risk.
"Quad bikes are inherently dangerous. On average five people are killed in quad bike accidents and another 850 are injured. They are not toys and need to be ridden with care.
"There was simply no excuse for Mr Holmes not wearing a helmet,'' she said.
"Helmets were supplied at his workplace but he chose not to wear one. A helmet can be the difference between walking away from an accident and suffering a permanent, life-changing brain injury.''
Quad bikes designed for one person should also not be used to carry passengers _ particularly children in a work environment, Ms de Rooy said.
"Mr Holmes repeatedly showed reckless disregard for safety. He is lucky that WorkSafe NZ inspectors intervened before there was any accident.''
It took so long to take legal action against Holmes because they were working through the full range of enforcement options available to them, she told Radio New Zealand.
"There have been a number of actions taken and it's a result of unsafe behaviour continuing that we have taken the next step.''
Prosecution was a "significant action'' and in this case resulted in a "significant fine'', Ms de Rooy said.
"In the majority of cases we are able to secure behaviour change much earlier down the track.''
