Maritime safety inspectors (MSIs) inspect all international and New Zealand vessels for safety and seaworthiness. They attend the scene of any maritime accidents or incidents in New Zealand waters and also provide advice to the public.

Maritime safety inspectors are based at all of the major ports around New Zealand. They are on-hand to help with information and advice for example about: marine laws, vessel registration, safety matters and occasionally even arbitrating between disgruntled boaties .

All Maritime safety inspectors are practical seafarers; having served at sea in senior positions, either in the engine room or on deck.

Ship safety inspections are a pivotal part of the work that Maritime safety inspectors do. They check for anything that could endanger the lives of a ship’s crew or which could put the marine environment at risk. This includes checking:

for unacceptable deterioration of the ship's structure
the qualifications of officers and crew
that operating practices are being followed, such as the maintenance of lifesaving and firefighting equipment.

If a vessel fails to meet safety standards, the Maritime safety inspectors have the power to detain the vessel in port until repairs are made to make it seaworthy.