Air New Zealand is working to minimise disruption for tens of thousands of travellers over Easter after some international cabin crew announced a four-day strike.

The airline has about 20,000 passengers booked over the Easter holiday weekend on transtasman and Pacific Islands flights.

It is training non-union staff to crew planes and looking at redeploying aircraft with staff covered by a different agreement.

The airline says it will also book passengers on other airlines if necessary.

The strike would come at a bad time for the airline as it faces a sharp drop in revenue from long-haul routes and intense competition in Australia, including from a growing number of budget airlines.

It would also be a sharp breakdown in staff relations after several years of industrial calm. The last action by flight attendants was in 2005.

Nearly 250 cabin crew on the short-haul international routes are covered by the Engineering, Printing and Manufacturing Union which yesterday said that following the breakdown of mediation, they would strike for four days from April 8.

The action does not involve domestic or long-haul operations.

The strike would end late on Saturday night of the long Easter weekend, but the entire weekend could be affected. It is one of the busiest travel periods and Air New Zealand could struggle to find seats on other airlines because they are also heavily booked.

The crew say they will begin low-level action this weekend by not wearing uniforms and refusing to do paperwork.

They will step this up next week by refusing to fill in for sick colleagues.

The crew are employed by an airline subsidiary, Zeal 320, and are paid at different rates to Air NZ domestic and long-haul cabin crew.

The union said Zeal 320 staff were being paid "poverty wages" and those working directly for the parent company received thousands of dollars more.

Air New Zealand's general manager of Tasman Pacific Airline, Glen Sowry, said the action was timed to "create as much havoc and disruption as possible".

He disputed claims crew would struggle to live on what they were being paid.

"Air New Zealand has shown it will not be intimidated or yield to industrial action by greedy unions that are out of touch with reality, particularly at a time when the global economy is melting down and people around the world are thankful for employment."

The crew had turned down a 4.5 per cent increase for 15 months "when thousands of New Zealanders are losing their jobs".

Contract talks started about six months ago, and it became clear at an early stage that they could break down.

"It hasn't surprised us that this notice has been issued. We've been working on the contingency that there will be a full withdrawal of labour."

Mr Sowry was confident the strike would have "little or no impact" on Air New Zealand passengers and said he was not relying on other carriers to bail it out.

The Zeal flight attendants were mainly formerly with Air New Zealand budget carrier Freedom Air, and it was important to keep costs down across the Tasman to remain competitive, he said.

EPMU national aviation organiser Strachan Crang said Zeal flight crew start on a lower base rate and missed out on many of the allowances paid to other Air NZ attendants.

They started on a base rate of $25,625, excluding performance bonuses and meal and transport allowances.

The airline says its offer would have given an average package of $41,000.

A crew member said average starting packages were around $37,000. Bonus payments were not guaranteed.

"Most importantly they want to move towards pay parity with other Air NZ cabin crew who do the same work," Mr Crang said.

He said the airline was facing resistance from those on individual contracts who could be asked to fill in for their striking colleagues.

One crew member, Kirsty Hamilton, said she and her colleagues were sick of "being treated as second-class citizens."

"We've got crew who go on trips away with work and can't afford to eat when they're at the hotel, so they don't, they wait until they get on board," she told Radio New Zealand.

Some were resorting to interest-only mortgages to free up money, and some of those taking on extra work were doing so after working shifts from 8pm to 8am, Ms Hamilton said.

Ms Hamilton said Air NZ crew had negotiated a satisfactory pay rise in tough economic times, and those at Zeal wanted the same.

"We just want to be respected and appreciated and get recognition for the line of work we do, and this (strike action) is the last resort," she said.

* Air NZ cabin staff who crew A320s plan to start industrial action this weekend.
* It will culminate in a four-day strike extending into the first half of Easter.