The Australian Services Union has accused Qantas of underpaying its staff for several years.
One worker claimed they were being paid level four wages despite being eligible for level five wages.
There are also claims the national carrier is preparing to force workers to work for even lower wage levels.
Qantas previously faced scrutiny for its illegal sacking of 1,700 staff during the COVID-19 pandemic.
The airline has also been accused of pressuring the Albanese government to block additional Qatar Airways flights from entering Australia.
(SKY NEWS)