Emergency services have been scrambled after an Air New Zealand Dreamliner departing from Auckland Airport reported a burning smell.
The Fire Service said the Boeing 787's crew reported a smell "like electrical burning".
Six fire crews were called to Auckland Airport shortly after 9.30am today.
The aircraft had been departing for Sydney before having to return, an airport spokeswoman said.
The Air New Zealand plane had landed and the rescue teams have been stood down.
Further details are being sought from Air New Zealand.
A Fire Service communications spokesman said it was not clear exactly what the issue was yet and they would know more after the plane had landed.
Air New Zealand spokeswoman Emma Field said the plane was being inspected by engineers after landing "without incident" shortly before 10am.
"Flight NZ103 from Auckland to Sydney returned shortly after take-off this morning as a precaution after an unusual smell was detected in the cockpit."
The Dreamliner had been taken out of service for the time being.
Customers booked to travel on this service were being re-accommodated on an alternative service, Field said.