Qantas has been accused of using the COVID-19 pandemic to kill workplace agreements with international flight attendants.

The Australian airline has applied to the Fair Work Commission to terminate its enterprise deal with long-haul cabin crew.

Cabin crews, their union and Qantas have made little progress in negotiations over changing the terms of the workers' agreement.

For the first time, Qantas now wants to tear up an existing workplace agreement.

University of Adelaide workplace law expert Andrew Stewart has described it as “taking the nuclear option”.

“It's the nuclear option in the sense that it's taking years and years of negotiated arrangements and just blowing them up — or at least signalling a willingness to blow them up in order to achieve a very, very different set of conditions for the affected staff,” Professor Stewart told reporters.

Qantas says it wants to adjust its Long Haul Cabin Crew Agreement “to change restrictive and outdated rostering processes”.

Currently, about 20 per cent of its 2,500 long-haul crew can only be used on a single type of aircraft.

The existing agreement prevents a cabin crew on the A330 fleet from alos operating on the 787 and A380 fleets.

The company says that deal is “unworkable as the airline seeks to recover from COVID”.

The workers' union, the Flight Attendant's Association of Australia (FAAA), and 97 per cent of staff who voted have rejected Qantas’ offer of more money and allowances.

“Asking to terminate the current agreement is the last thing we want, but we're stuck between a rock and a hard place,” Qantas International's chief executive, Andrew David, said in a statement.

“We're seeking termination because we can't effectively run our business without the rostering changes we desperately need to properly restart our international network in a post-COVID world.

“The FAAA ran a scare campaign against the new deal, claiming it would mean redundancies and offshoring, despite the fact that we're currently hiring new crew in Australia.

“The union's default position is that the company can't be trusted and should always give more. That's simply wrong.”

FAAA federal secretary Teri O'Toole says those comments are “completely untrue”.

“We didn't run a scare campaign at all. It's simply untrue,” she said in response.

“The changes they wanted would have resulted in less flexibility and work-life balance.

“The equivalent is if you go to work for four weeks and one of those weeks you have no idea where you'll be. You can't plan your life.

“Cabin crew are no longer single people. They aren't so inflexible that they can have this insecurity.”

The Australian Council of Trade Unions (ACTU) says that if the Qantas application to the FWC is successful, some of the flight attendants could see wages cut by half.

“Qantas has received billions in taxpayer funds over the last two years,” ACTU president Michele O'Neil says.

“Now they are threatening workers to try and force through a deal, slash wages and keep more of our money for themselves.”