Ground handlers from Dnata, who are contracted to Qantas and other airlines, will walk off the job for 24 hours on Monday, September 12.
The industrial action was agreed to by Dnata workers on Friday with some 350 crew to strike.
It follows calls by the Transport Workers Union for Dnata to lift pay and conditions, including minimum guaranteed work hours.
Qantas sacked its own ground crew staff during the height of the COVID-19 pandemic and moved to outsourcing roles to companies such as Dnata.
An airline spokeswoman said the negotiations were a matter for Dnata and the carrier had contingency plans in place to curb disruptions.
The transport union's national secretary Michael Kaine said ground handlers couldn't afford to stay in the industry because of a drop in pay and conditions.
"We need to rebalance aviation towards good, secure jobs that keep skilled workers in the industry and ensure the safety of the travelling public," Mr Kaine said.
He pinned the fall in conditions on Qantas' outsourcing and the lack of JobKeeper payments for Dnata workers under the former Morrison government.
Mr Kaine called on the new Albanese government to establish a regulatory body to set minimum standards across the industry.
Qantas is challenging in the High Court a recent Federal Court decision declaring the airlines' outsourcing of 2000 ground crew workers as illegal.
If it loses the appeal, Qantas could owe compensation to the nearly 1700 workers it sacked during the pandemic.
Dnata crews provide ground handling services to Qantas international flights in Sydney, Melbourne and Brisbane.
It does not do baggage handling for Qantas domestic flights.
The airline spokeswoman said Dnata provided services to more than 20 airlines across Australia and would have potential impacts across the sector.
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