Disruptions are expected across Australia's international airports on Monday as thousands of Border Force workers strike for 24 hours.
About 5000 workers support the strike action, and while not all will be able to take part, it's likely the bulk of those rostered on will stop work from midnight on Sunday.
"Staff will strike for 24 hours at international airports, ports, mail and cargo centres to protest government threats to cut their pay," CPSU national secretary Nadine Flood said, adding that cuts to conditions would cause some workers to lose about $20,000.
Border Force staff who clear passengers and cargo will be involved in the industrial action, but those involved with counter-terrorism and national security will work as usual.
"We don't want to inconvenience passengers but we would suggest that people get to airports early," Ms Flood said.
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Under the proposed cuts, part of a year-long dispute between the union and the government, allowances for extra duties would be slashed to a standard $2000 payment.
This would decrease many workers' pay by about $8000, Ms Flood said.
"There's a range of allowances such as firearms, fitness and so on," she said.
"We have officers in Border Force who face losing $20,000 because they're in more specialised roles," she said.
Last week the government offered to lift the pay cap to two per cent, but hasn't budged on other proposed cuts.
Similar strikes were held six weeks ago.
But Monday's action represents an escalation, with previous airport strikes limited to two hours.
Ms Flood said she would prefer to meet with the government and resolve the issues rather than have more industrial action.
Lobby group Tourism & Transport Forum Australia has said the strike action could harm the country's reputation.
"Efficient border processing is critical to the visitor experience," the group's CEO Margy Osmond said.
