The unusually hot and dry weather has been blamed for Auckland Airport's deteriorating runway.
The airport has completed a review after two recent runway closures which stopped flights from landing for more than an hour in one case.
In January, pieces of broken concrete up to 30cm by 30cm and 12cm thick had been reported on the runway.
International pilots say maintenance of the runway has not kept up with the rate that it's deteriorating.
Auckland Airport chief executive Adrian Littlewood told Checkpoint they had looked very closely at the event and found the runway is safe.
"We did have two defects on the runway that took longer to repair than they should have otherwise taken, and that did disrupt people's plans and we apologise for that."
Littewood said the defects were caused by a combination of factors including thermal expansion and impact from landing planes.
"The team were monitoring that and acted quickly to get it repaired, but it did take longer than expected and we apologise for that."
Some pilots said that large chunks of concrete were displaced on the runway and that hitting that kind of debris at the speeds they land at would be like hitting a bullet.
But Littlewood said they know their runway well and the review concluded it is safe.
"Our condition is to standard and our maintanence and management is absolutely to standard.
"We can confirm absolutely the runway is safe... we had that independently verified."