Travellers trying to enter or leave Australia on Monday face massive delays as passport handlers prepare to strike for 24 hours.
Thousands of Border Force officers will strike at international airports, seaports and mail centres next week over a pay offer they say will leave them at least $8000 a year worse off.
Additional industrial action is also planned for Wednesday this week with the Community and Public Sector Union (CPSU) moving to enforce limited work bans at air and freight ports and mail centres.
But Monday's round-the-clock action represents a dramatic escalation in an industrial campaign that has been playing out for months, with previous airport strikes limited to two hours.
It will represent a much bigger headache for operators as officers who check passports and process departure and arrival cards at Australia's international airports will be among those participating.
It will also involve inspectors who check international freight for contraband like weapons and drugs.
CPSU National Secretary Nadine Flood says union members are outraged by the Department of Immigration and Border Protection's determination to strip allowances that will cost workers thousands each year.
Ms Flood said Wednesday's action will go ahead, despite the department saying staff who fail to complete 100 per cent of their duties will lose an entire day's pay.
"This amounts to a management-initiated strike," Ms Flood said on Tuesday.
"If the department wasn't standing down these workers without pay for a limited work ban, they would be at work continuing with the majority of their duties."
About 500 workers are expected to take part in Wednesday's action, but the number will be well into the thousands on Monday, the union said.
AAP is seeking comment from the department and major airports about their contingency plans.
Sydney and Brisbane airports declined to say what specific contingency plans would be put in place to minimise disruptions to travellers.
