"This suggests the tyre may have made contact with a runway light," the spokesperson said.
"The aircraft was checked after returning and went back into service this morning. The safety of customers and crew is paramount and non-negotiable which is why the pilots elected to return to Christchurch, so the aircraft could be inspected immediately by engineers."
A statement from Air NZ last night said it was believed a wheel in the main landing gear had made contact with an object on departure.
"The aircraft made a normal landing ... and will be inspected by engineers,'' Air NZ said.