Air New Zealand engineers are at Hawke's Bay Airport carrying out an examination of one of the engines on an ATR72 aircraft which had to be grounded mid-morning after a light haze was detected in the cabin prior to take-off.
An Air New Zealand spokesperson said the engineers arrived to carry out checks early this afternoon.
It was not known what had sparked the haze but smoke had been ruled out.
"Not sure at this stage what it was," the spokesperson said.
"The engineers are onto it."