Both incidents involved the engines during climb on takeoff from Auckland, forcing them to turn back.
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.
In a statement released today the Transport Accident Investigation Commission say they've opened inquiries into both events, with investigators having been on the ground in Auckland since Tuesday.
Air New Zealand will cancel six worldwide flights and retime others between 7 and 10 December to accommodate urgent maintenance on the Rolls-Royce Trent 1000 engines that power its Boeing 787-9 fleet.
Rolls-Royce did not have spare engines available while the maintenance work was being undertaken, Air New Zealand said in an announcement to the stock exchange.
Air New Zealand will operate its new configuration 787-9 aircraft, offering more Premium Economy and Business Premier seats than its current 787-9 fleet.
The Aviation Analysis Wing website reports this is the second engine vibration incident involving Rolls Royce Trent series engines this year.
Customers affected by these changes will be proactively contacted with new travel information. Boeing has had a programme of replacing rear turbine blades on the Trent 1000 engines. A few weeks later Virgin Atlantic said it was had also experienced similar troubles with its Trent 1000 engines. From October 2018 the airlines will increase to three daily services operating a combination of A380, Boeing 777 and Dreamliner 787-9 aircraft.
"Rolls - which has more than 400 of the US$10m engines in service - has acknowledged the problems. This is the continuation of work which started a year ago to upgrade Trent 1000 engines to the latest standard".
Rolls-Royce said it was working with Air New Zealand to minimise disruption and vowed to restore full flight operations as soon as possible.