An Air Chathams flight bound for Whanganui from Auckland had to make an emergency landing at Hamilton Airport on Monday due to an electrical fault.
The fault caused a detector to register heating in the rear cargo area of the Saab 340.
The aircraft and its 31 passengers were not able to continue to Whanganui until the aircraft had been inspected by engineers who had to travel from Auckland.
Air Chathams chief executive Craig Emeny said it caused a four to five-hour delay before the aircraft was approved to resume the flight.
Emeny said it wasn't a fault the airline had previously encountered.
"There are a lot of rules around what we carry and where we carry it, so the chances of actually getting overheating or a fire in that area is extremely low," he said.
"Staff are equipped with a detection system and it was that detection system that failed. It wasn't actually anything that went wrong with the cargo."
Every six months staff are required to do simulation training in Melbourne which covers the issue that occurred during Monday's flight.
Emeny said the airline will look at ways to mitigate the "false warning" from happening again.
"The aircrafts go through regular checks but, following on from this, we will carry out an investigation into what happened and why, but largely we already know because the aircraft wouldn't have been released for service unless we did."
The delay meant Monday afternoon's Whanganui to Auckland flight had to be cancelled.
Emeny said all passengers due to travel on the cancelled flight were reallocated to flights for the next day.