The farming company, Greystone Holdings Limited, will also voluntarily pay reparation of $15,000 into a trust account of the victim.
Worksafe is using the incident as a reminder to the public that children and quads don't mix.
WorkSafe Deputy General Manager, Investigations and Specialist Services Simon Humphries said that whether you own a small holding or a high country station, children do not belong on adult-sized quad bikes as riders or passengers.
"It might look like fun and a way to keep the kids amused but the risk of death or injury needs to outweigh the entertainment factor - there is little contest between a quad and a child," Humphries said.
"These are heavy and powerful machines that require the rider's full attention. A child does not have the physical strength or risk recognition to be an independent passenger, especially on a vehicle that is not designed for carrying extra people."
WorkSafe's investigation found that while Greystone was aware of the dangers associated with quad bikes, it still allowed children to ride on the quad on occasion.
It also found that Greystone should have directed its workers that only one person was to ride the quad at a time and that children were not to be carried as passengers.
"The dangers associated with quads are very well known. There is considerable guidance available that clearly states that children should not ride on quads," Humphries said.
"This was a lucky escape and a reminder to other farm owners, especially families on farms, to think about how their kids are interacting with the farm business and how they can be sure to keep them safe."