The Health and Safety at Work Act 2015 covers the safety of employees and contractors wherever they are working for you, and this includes when they’re in a vehicle driving for work, whether they are driving or just a passenger.
What this means is that they must have a licence for that vehicle (if they are driving), the vehicle must be roadworthy and that there must be adequate first aid supplies available to deal with any injury that could occur. Travelling first aid kits are readily available for $30-40 and can fit in the glovebox or boot. They may need to be refreshed periodically if there are items in them that expire.
Other safety equipment that remote workers or workers working alone in the field must have is a way of contacting based which is reliable. A cellphone plus a GPS, CB radio, satellite phone or locator beacon is usually sufficient.
NZTA recommends that: all vehicles should be fitted with a fire extinguisher, a first aid kit, a torch, a reflective vest and an emergency triangle.