Air New Zealand is battling to cope with the massive increase in customer enquiries following the Prime Minister's announcement of travel restrictions yesterday.

To meet the demand, the airline is boosting the size of its contact centre and social media customer-care teams.

Air New Zealand senior manager of customer care Doug Grant says this is an unprecedented situation and that the airline is dealing with a very high volume of customer enquiries through its channels.

"We have brought in additional staff to assist and are actively prioritising customer queries," he said.

"To ensure urgent cases are dealt with as quickly as possible, we strongly encourage customers to only contact us if their flight is departing within the next 48 hours."

Yesterday Ardern announced that any person from any country, excluding the Pacific islands, is now required to self-isolate for 14 days upon arrival to the country, and she encouraged all New Zealanders to avoid all non-essential travel overseas.

As well as affecting thousands of people's travel plans, the move is expected to significantly impact Kiwis' jobs and the New Zealand economy.

The measures are set to take effect from midnight on Sunday.

Grant advised customers to check the Air New Zealand Travel Alerts page for information before getting in touch.

"We really appreciate the patience and understanding of all our customers at this difficult time," he said.

• Coronavirus travel restrictions predicted to 'kill' tourism industry

Air New Zealand is offering fare flexibility for customers affected by Covid-19 travel restrictions.

Customers with international flights affected by Covid-19 Government-imposed restrictions due to depart up until 31 March 2020 will be eligible to hold the value of their fare in credit for twelve months from the time of ticket purchase, receive a refund, or amend the date of their flight without change fees