New Zealand's Civil Aviation Authority (CAA) is to investigate an incident that led to the grounding of all non-airborne flights across the country.
The flights were grounded today until 4pm (local time) due to faulty radar.
Although several flights resumed operations after two hours of being grounded, many flights are likely to be delayed due to the technical glitch in the radar system operated by the country's only air traffic service (ATS) provider Airways New Zealand.
Airways New Zealand said that around 50 airborne flights had been affected due to the incident and that it had backup processes throughout the outage to tackle the issue safely.
The company said in a statement: "Flights are now departing but the backlog will take some time to clear as approximately 160 international and domestic Air New Zealand flights have been impacted this afternoon and into this evening."
The outage resulted in air traffic controllers having to revert to emergency procedures to help 50 airborne planes to land. The controllers were in direct contact with pilots to understand the positions of the aircraft.
The CAA said in a statement that it was also working on preventing reoccurrence of such an outage.
A spokesperson said: "At no point were any passengers or aircraft at risk, due to the immediate implementation of Airways contingency planning procedures.
"The system was thoroughly tested and fully stable by 3.30pm. Flights returned to partial operation by 4pm and then were fully operational at 4:30 pm.
"Flights were resumed on a priority basis with major trunk routes and jet flights being resumed first."