Flights were grounded and around 300 passengers and staff were told to leave the terminal after a bottle containing liquid and wires was found in the men's toilet about 9am this morning.
Passengers had to endure a five-hour wait outside amid fears the bottle was an "improvised explosive device".
Army bomb experts, who arrived around noon, neutralised the device using a bomb disposal robot.
Police Incident Controller Inspector Alastair Dickie said the disposal operation did not trigger any further explosions.
Police then conducted a sweep of the terminal.
The sweep found nothing suspicious except wires in a rubbish bin in the main terminal. The significance of these was yet to be determined.
"The scene where the hoax device was found has been secured and the airport is now open again," a police spokesman said.
Passengers were allowed back in the terminal at 2.10pm and the first flight was due to leave for Christchurch at 2.40pm.
Inspector Dickie thanked the public for their cooperation and understanding.
People affected by disruption to flights were asked to check with Air New Zealand for flight information.
