However, around 8am the flight landed safely, an Air New Zealand spokesperson said.
"The crew operating NZ5025 from Auckland to Napier this morning received a maintenance alert during the service," they said.
"As a precaution and in line with standard operating procedures, emergency services were on standby at Napier Airport. The aircraft landed safely and our maintenance team will now inspect the aircraft before it can return to service."
Shift manager Chris Dalton earlier said three crews were at the airport as a precaution after an aircraft indicated a possible "situation on board".
He said larger airports had their own fire brigades, but in regional areas FENZ was called in to help.
Dalton said there had been no suggestion of an emergency.
