Qantas workers were planning to rally in Canberra to protest against the airline's proposal to have its baggage handling and other airport services done by outside companies at eleven airports, including Canberra.

The union said that the legal action would be filed in the Fair Work Commission on Thursday morning.

Its allegation is that Qantas failed to go through agreed legal procedures and consultation before announcing the plan.

"Qantas has given workers just six weeks to make a final bid and to find $80 million to fund equipment upgrades, despite the airline choosing not to do these upgrades when it made almost a billion dollar in profit last year," the union said.

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TWU National Secretary Michael Kaine said: "Qantas has torn up the agreements and the rulebook on how to act like a responsible corporate entity and has turned on its own workforce and the taxpayers.

"Scott Morrison has a simple choice: he can either stand with Qantas workers and the taxpayer or he can support Alan Joyce and his spiteful management team."

Qantas argues that big changes need to be made as the airline fights to stay alive in the face of the current unprecedented global crisis which has seen virtually all international travel closed down.

The union argues that it is using the crisis to mask changes it doesn't need to make.

"The Qantas CEO is now back earning millions while the airline has pocketed $800 million in taxpayers funding between Jobkeeper and public money to fly planes," union official Michael Kaine said.

He said that Qantas had received around $800 million in federal funding, including $490 million to subsidise wages to retain jobs and to keep domestic and international routes operating.