The Prime Minister says he decided to reimburse the owners of a helicopter for a ride within 48 hours of making the journey.
John Key had been opening a Waikato walkway when he accepted a ride back to Auckland in a helicopter owned by Peter and Philip Vela in December 2009.
Mr Key then gained retrospective approval to reimburse the Vela brothers $2000 for the ride.
The Labour Party says Mr Key paid for the ride to avoid it appearing as a gift on the register of pecuniary interests.
On Tuesday, Mr Key told Parliament he needed to return to Auckland in time to attend security-related meetings.
However, he refused to say whether he would have made the meetings if he travelled by car.