The Aviation Security Service (Avsec) could bring in the police to replace locked-out airport security staff if a strike goes ahead in the school holidays.
The agency says the plans are well advanced and the E tu union is calling it "a highly aggressive move".
Avsec has activated its National Contingency Plan to potentially use outside trained staff at airport security gates during the lockout. Yesterday Prime Minister John Key suggested the staff replacements could come from police or Customs.
However the Police Association doesn't want its officers involved in the looming strike action.
"It's the police's role to ensure they do keep peace, and they could be in the situation where they are not only carrying out the role but also trying to enforce the peace. So I do think there could be a big conflict of roles," Association president Greg O'Connor says.
Avsec has issued lockout notices to airport security union members, escalating the threat of airport chaos for travellers from July 20.
The lockout notice sent by Avsec to unions indicates it will be for one day, barring security staff from their workplace.
The unions say they're surprised and disappointed as they were to have held mediation talks on July 15 aimed at preventing strike action.
It's the first time airport security staff have threatened to walk off the job in 30 years, and the biggest industrial dispute in recent times in New Zealand.
E tu believes a deal can be reached between airport security staff and the Aviation Security Service if the agency is prepared to listen.
E tu head of aviation Kelvin Ellis says striking is not something their members want to do.
"We've got to deal with a situation in front of us which is resolving this dispute, and avoiding massive disruption in industrial action in two weeks' time.
"Let's be clear our members don't want to do this. They don't want to disrupt the travelling public, they don't want to lose money by standing outside their workplace.
"What they want is for the company to genuinely listen to them, show them a bit of respect, and to actually fix this."
House of Travel says it's unlikely passengers will be able to change their flights in order to avoid strike action by airport staff.
Commercial director Brent Thomas says travellers will just have to weather the delays as airlines will already be under pressure.
"Typically they won't allow changes but that'll come down to an airline decision," he says.
Mr Thomas advises travellers to arrive at least an hour early for their flights early to combat expected delays during the busy school holiday period.
He is hopeful a solution can be reached between the two parties before the strike is implemented in two weeks' time.