The Department of Labour says about a third of the farms it has visited over the past two months have not been complying with quad bike safety rules.
Health and safety inspectors have visited 225 farms as part of the department's quad bike safety campaign, launched last year.
They have issued 76 improvement notices, written warnings and prohibition notices.
The first round of visits which ended in June resulted in 117 warnings being given.
However, the department says there has been an increase in quad bike helmet purchases and this has translated to more being worn on the farm.
It says that's important because 40% of quad bike fatalities involve head injuries.
Each year about 850 people are injured while riding quad bikes on farms.