Wellington  - Nearly 250 flight attendants employed by an Air New Zealand subsidiary will go on strike for four days on May 7 after what their union says is a seven-month fight for equal pay with the airline's other cabin crew.

The Engineering, Printing and Manufacturing Union said all Air New Zealand flights to Australia and Pacific island destinations serviced by the airline's Airbus A320 fleet would be affected.

The airline, which is majority-owned by the New Zealand government, said it would lock out the union members and man the planes with other employees and services would not be disrupted.

Union secretary Andrew Little accused Air New Zealand of "unethical use of corporate legal structures" in establishing the subsidiary, Zeal 320, to pay the 240 workers up to 30,000 New Zealand dollars (16,500 US dollars) a year less than other cabin crew.

"The only people who are employed by Zeal 320 are these flight attendants because the company exists solely to exclude them from the terms and conditions other crew enjoy," Little said.

The airline said it had offered a 4.5-per-cent pay rise which the union had jeopardized by walking out on mediation talks.(dpa)