Unions representing aviation security workers have been issued with "illegal and irresponsible" lock-out notices over their plans to take strike action, the organisations say.
The lockout notices would take effect over an eight day period from 20-27 July.
Yesterday the Public Service Association and E tū agreed to take part in mediation on the 15 July.
But if a deal over pay and conditions cannot be reached, strikes at both airports would start in two weeks' time.
Now the unions are calling on the Transport Minister to intervene to stop his agency "flouting the law".
In a statement, they say they have written to the Aviation Security Service to ask that the lock-out notices be withdrawn.
E tū National Organiser Kelvin Ellis said this was "an extraordinary step".
"Yesterday the Minister of Transport claimed our mild industrial action was designed to cause disruption - and today his agency is taking an aggressive and illegal move that will cause chaos," he said.
The PSA was "stunned by the level of aggression" being shown by the Aviation Security Service, particularly as all parties had agreed to mediation next week.
Don't use police as strike-breakers, govt told
Meanwhile , the Police Association said the government should not even be contemplating using police to break a possible strike by aviation security officers.
Before mediation was agreed to yesterday, Prime Minister John Key said he was not ruling out using other agencies such as Customs or police to avoid disruption if the strikes went.
Police Association president Greg O'Connor said it would be a considerable conflict of interest if police officers were crossing the picket line and breaking the strike, while also being expected to maintain order.
"I think it would be unwise to contemplate using police as strike-breakers in cases like this. The role of police of course is to preserve the peace, to ensure there's no breach of the peace, and often around industrial disputes there can be breaches around picket-lines," Mr O'Connor said.
"And for police to be on one side of the picket line and on the other hand trying to police the picket line would be a difficult situation to say the least."