Industrial action at Sydney Airport's international terminal has increased waiting times, leaving some passengers frustrated.

Border Force and Immigration workers are conducting stop-work action for four hours each day over the coming 10 days, at eight international airports around the country.

In Sydney, hundreds of passengers have been confronted by lengthy queues.

One passenger told the ABC that some people were frustrated by the wait.

"People pushing, pushing their bags. They're getting upset, we're getting upset," he said.

Several passengers said they were not told about the industrial action, leaving them guessing about the cause of the delays.

"I didn't even know there was a strike until we just walked out and that was the reason for it," one man said.

"Try living in another country ...we have it so good here and we just don't know it."

Community and Public Sector Union national secretary Nadine Flood said the Federal Government planned to cut workers' conditions allowances, severely cutting their take-home pay.

"They're looking at getting cuts to current pay of up to $8,000 a year," she said.

"Border Force and Immigration do a very tough job, often a difficult and dangerous job.

"They deal with bikie gangs, ice importation, guns, organised crime."

Passengers avoided disruptions at Melbourne Airport this morning, despite Border Force workers stopping work at the international terminal.