The unions representing Air New Zealand Engineering and Logistics say their planned strike on December 21 will extend for three days.
On Tuesday they confirmed that last week they issued three full-day strike notices for December 21, 22, and 23.
The news comes after negotiations on Monday, which extended late in to the night as officials and union delegates tried to reach an agreement.
Air New Zealand General Manager Customer Experience Anita Hawthorne said at this stage no flight delays or cancellations were in place.
The airline would do all it could to get customers where they need to be this Christmas, she said.
“We know customers are very concerned about their travel plans at this important time of the year and unfortunately we are not in a position to provide certainty at this time.
“We would like to reassure customers that we remain committed to mediation with unions and we are still hopeful of reaching a resolution which sees strike action averted.”