The flights must be booked by that time and must be taken by June 30 2023. This applies to both domestic and international credits.
Alternatively they could also amend the date of their flight.
Air New Zealand's chief customer and sales officer Leanne Geraghty says the changes will give customers added certainty.
"We've seen many of our customers using their credits already and we're hopeful Tasman and Pacific travel will be up and running over the coming months," she said
"For those wanting to go further afield, we recognise this may take longer, which is why we've extended the window for opting into credit as well as the length of time people have to use that credit."
Today's announcement comes as the Government remains cautious about opening borders to quarantine-free travel between Australia and New Zealand.
With the Covid pandemic heavily impacting on international passenger travel, Air NZ has been under pressure to review its hardline refund policy and to clarify how long passengers' credits will be honoured, amid the ongoing uncertainty over international travel.
Consumer NZ has said the airline needed to clarify as soon as possible its stand on extending a booking window to avoid renewed frustration over refunds and credits.
The airline earned the dubious title of the most complained about company to the Commerce Commission last year for one of the worst customer relations crises in its 80-year history.
