The Civil Aviation Authority has issued an alert for microlight pilots after a fatal accident in February.
Two men died in the Airborne XTS-912 microlight accident in Abel Tasman National Park.
The CAA says it appears the aircraft broke up during flight.
The authority says an aluminium part on the popular Australian-built microlight may not be up to required specifications.
Recreational Aircraft Association president Evan Gardiner is urging careful checks of aircraft before flights, to ensure there is no sign of corrosion or stress in the air frame.