"This change will give them the flexibility to change their plans, so they don't miss out on their holidays or being reunited with friends and whānau, and they can still get to where they want to be at a later time."
In a statement, Air NZ said those booked between now and July 31 could keep their fare as a credit for 12 months. The credit could be lodged online and the airline asked people only call if their flight was leaving in the next 48 hours.
Geraghty said the airline's call centre was under "enormous" pressure with illness and weather disruption.
Customers who booked through a travel agent or third-party online agent should contact them directly about making changes to their bookings or credit validity, she said.