Air New Zealand has dropped its direct flights between Auckland and Norfolk Island because of declining passenger numbers.

The flights will cease in May 2017, but passengers will still be able to fly to Norfolk Island with the carrier using connections through Sydney and Brisbane.

"The Auckland-Norfolk Island route is not commercially sustainable so it makes sense to focus our operations out of Australia, where there's good potential," general manager networks Richard Thomson said.

Air New Zealand said the small number of customers holding bookings on the Auckland-Norfolk Island flight after May 2017 could instead travel there via Australia, put their fare towards another destination or get a full refund.

The airline's flights to Norfolk Island will continue to leave from Sydney twice a week and Brisbane once a week.

During the peak season from September to April, five flights per week will leave.