Air New Zealand has agreed to extend customers' credits until June 30 next year.
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."
Air New Zealand has criticism over its reluctance to offer refunds and the hardline nature of its credit policy.
Today's announcement, following an internal review of its credit policy, 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.
Geraghty previously said it was impossible to predict when borders may be open.
'We recognise that changing circumstances paired with other things needing to line up, whether that's flights, pre-departure testing or managed isolation, can make things tricky,'' she told the Herald.
The prospect of international travel has also been delayed by the rollout of the Government's vaccine programme.
This week, the Government announced the Pfizer/BioNTech vaccine has jumped its final approval hurdle and after being given the tick by ministers.
The Government still doesn't have a firm date for when the Pfizer vaccines will arrive but health boards have been warned to "be ready".
Border workers like nurses, security staff, customs and border officials, airline staff and hotel workers and their households will be the first vaccinated when the first batch arrives by the end of next month.
It remains unclear how long it will take for the broader population to be vaccinated.