An investigation is underway after two Air New Zealand 787 aircraft experienced engine abnormalities in recent days.
The airline is cancelling and rescheduling some international flights due to the incidents.
On Tuesday morning an Air New Zealand 787 bound for Narita, Japan experience engine abnormality, and returned to Auckland airport after the crew shut down the engine.
Last night another Air NZ 787 aircraft bound for Buenos Aires also experienced engine abnormality and made an "uneventful return" to Auckland airport.
Transport Accident Investigation Commission (TAIC) chief commissioner Jane Meares said the commission has opened inquiries into both events.
TAIC is working closely with the airline, Civil Aviation Authority and engine-manufacturer Rolls Royce. They're also likely to work with aircraft manufacturer Boeing.
"Our investigation team is securing and reviewing aircraft records including recorder information, making preliminary examinations of the engines, and interviewing company representatives and the flight crew," Ms Meares said.
"At this stage our investigation team is satisfied that all parties are doing the right things to ensure the continuing safety of the travelling public. Should the Commission believe that insufficient action is being taken at any time then it has the ability to issue urgent recommendations while its inquiries continue."
Air New Zealand will be making cancellations and rescheduling some international flights due to the incidents.
"Rolls-Royce has advised that some of the Trent 1000 engines in the airline's Boeing 787-9 fleet require maintenance sooner than previously indicated," Air New Zealand said in a statement.
Passengers affected will be contacted, and the latest information will be published on the Travel Alerts section on Air New Zealand's website.