National's workplace relations spokesman Scott Simpson said calling a strike on Air NZ's busiest day of the year was designed to maximise disruption.
"This is exactly the sort of strike the Prime Minister told us wouldn't happen. Labour is taking us back to 1970s-style adversarial union activity except back then it was Cook Strait ferry unions disrupting Christmas," Simpson said.
Simpson said the move came on top of news that petrol tanker drivers would strike in the lead-up to Christmas.
Jared Abbott of First Union said 180 fuel tanker drivers at Pacific Fuel Haul had voted to walk off the job from December 16 for five days.
The drivers, who have been negotiating with Pacific Fuel Haul since August, were striking to protect modest redundancy provisions and for a fair and reasonable wage increase, he said in a statement.
"Fuel tanker drivers are at the most dangerous end of the most dangerous industry. We have over 60 truck-related fatalities every year. We need to maintain wage relativity to prevent more experienced drivers leaving the industry."
Pacific Fuel Haul said it was extremely disappointed by the intended strike action, particularly the timing for the busy week before Christmas.
Chief executive Stephen Ow les said: "We are concerned at the impact of the strike on New Zealanders just before Christmas. PFH will be working with other staff and drivers to minimise disruption and maintain supplies during the strike period."