Industrial action is upsetting passengers at Sydney Airport's international terminal this week, as strikes increase waiting times.

Border Force and Immigration workers are stopping work at eight international airports around the country for four hours each day for 10 days from Monday.

While passengers are complaining about not being told about the industrial action, Community and Public Sector Union national secretary Nadine Flood says it is a necessary move.

She claims the workers are taking action to stop Federal Government plans to cut workers' conditions allowances, which would lead to a big drop in 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.”