Part of Auckland Airport's international arrival terminal is flooded after its sprinkler system was activated.
Fire shift manager Colin Underdown said around 30 fire crew had been called to the site just before 4pm.
Airport spokesman Simon Lambourne believed a construction worker might have accidently set the sprinklers off.
He said aside from minor damage to two of its screening machines the flooding had not been significant.
Mr Lambourne said there might be a slight delay, but did not think it would cause a significant hold up in those going through customs.