The strike planned for Friday - less than two weeks out from Christmas - comes after the budget airline rejected workers' demands for pay increases, minimum hours on the job and safety improvements.
Speaking alongside workers at Sydney Airport on Tuesday, Transport Workers Union national secretary Michael Kaine said the airline needed to explain why it had rejected the "modest" requests.
"Jetstar won't listen when these workers say to them that they simply can't survive on 20 hours of work a week ... when they make sure Jetstar knows they are on the lowest pay in the industry," Mr Kaine said.
"They are finding it harder and harder to support their families and Jetstar won't listen when these workers repeatedly say that their jobs are not safe because there are too few workers lugging around thousands and thousands of kilos of baggage and having to service overlapping aircraft."
Negotiations between Jetstar and the union broke down after the company rejected worker demands including more rest breaks, a guaranteed 12-hour break between shifts and a guaranteed 30 hours a week of work.
Jetstar staff will walk off the job on Friday at Sydney, Melbourne's Tullamarine and Avalon airports as well as Brisbane, Cairns and Adelaide airports.
In a statement released last week, Jetstar chief executive Gareth Evans said strong arm TWU tactics would not change the airline's stance.
He said the union's demands would put "significant pressure" on the low fares the airline's customers rely on and force it to review its investment in new aircraft, technology and destinations.
