Department officials said the safer use of quadbikes was part of prioritising farm safety in general. They warned their patience about risky behaviour was being exhausted as this year's death toll from farm quadbike accidents reached six.
The department's chief health and safety adviser, Geraint Emrys, said, in the immediate future, staff would work with farmers, but from next April inspectors might start issuing infringement notices and spot fines of up to $3000 for breaches of the Health and Safety in Employment Act.
"We are making this a priority and sending a clear message out there," he said.
Inspectors have been instructed that if they see a quadbike in use, they are to visit the farm, which they can do legally, and discuss quadbike safety with staff and the farm owner.
"In the past, we might have carried on by, but because quadbike safety is a priority, we will therefore follow up what we see," he said.
Federated Farmers board member Donald Aubrey said his organisation supported the campaign to reduce quadbike death and injury. He said it was long overdue, but questioned the merits of spot checks, saying inspectors might not get a warm reception.
"If an inspector jumps the fence to talk to a farmer who has operated a machine safely for many years and tells him that on that particular day they are operating it unsafely, he may not get a good response."
He hoped inspectors would acknowledge the difference in risk from using a quadbike on flat land and using it on hills.
This harder-nosed approach by the Department of Labour was in response to the continued rate of farm quadbike accidents, with five people on average being killed annually and another 850 injured.
The department and industry earlier this month launched a quadbike safety campaign aimed at reducing death and injury from riding the widely used farm vehicles.
Farms were a work site and riding quadbikes was a workplace activity. Mr Emrys said farm employers were no different from other employers, and were required to take all practicable steps to ensure their staff's safety.
That meant ensuring safety guidelines recommended by quadbike manufacturers were followed, such as wearing helmets, load restrictions and use limitations.
Mr Emrys said staff could prosecute if the department believed the Health and Safety in Employment Act had been breached.
"If we need to, we will bring a case before the court."
Inspectors would ask if the rider was trained, if the employer provided safety gear such as a helmet, if the rider knew the vehicle's limitations, if the employer had advised the rider to limit speed and to avoid hazardous routes and had ensured the rider was not doing more than one task.