Thousands of passengers were left stranded on Tuesday afternoon as a radar fault cause the delay of 200 flights.
Airways, which monitors New Zealand’s airspace, said it noticed a fault at about 2.40pm. From that point on every commercial plane in New Zealand had to be cancelled. Those planes already in the air could land, but those yet to depart were grounded.
The radar went back into full service at about 4.30pm but delays to flights continued into Wednesday.
The Civil Aviation Authority (CAA) says it will investigate what caused a radar fault.
Air traffic controllers had to revert to emergency procedures to allow about 50 planes already in the air to land.
She said controllers had to rely on communicating directly with pilots to work out the position of planes.
Airways also said the cause of the fault was an internal network failure. It did not go into detail about what that meant but said no passengers were at risk.
It apologised for the inconvenience caused by the radar problem.