The "noisy" protests are expected across Sydney, Melbourne, Perth, Adelaide and Gold Coast airports from 11am on Wednesday, the Transport Workers' Union says.

They will demand better pay rates and more guaranteed hours, as well as an end to "deliberate understaffing" which the union says is a safety risk.

Up to 200 workers are expected to protest for about an hour across the five airports, with rallies in Perth, Coolangatta and Adelaide beginning at 11am, in Sydney at 12.15pm and Melbourne at 1pm.

The protests are not aimed at disrupting flights.

"We're not intending to cause disruption and our protesters won't be walking off the job, there won't be any strikes," union spokeswoman Judith Crosbie told AAP on Tuesday.

The protests are part of a bigger union campaign to push for better conditions in more than 200 pay deals spanning the road and air transport sectors, which are due to run out next June.

While pay agreements are not negotiated with the airports themselves, Ms Crosbie said they ultimately benefited from deals cutting wages and working conditions.

'What we're basically saying is, actually, the whole system is a bit messed up,' she said.

Australian Associated Press