Qantas redundancies 'half-baked': union

Up to 4500 Qantas workers will be given till the end of March to take or leave a "half-baked" redundancy package, unions say.

Australian Services Union (ASU) NSW branch secretary Sally McManus said Qantas would issue the staff on Thursday with expressions of interest in redundancy.

"4500 Qantas staff are going to be given a slip of paper and be asked whether they want to go - that's going to happen today," Ms McManus told AAP.

She said although the deadline on the offer for most workers was the end of March, workers at Sydney international airport had a deadline of March 21.

"There's either no plans about they want to do in those areas or half-baked plans, or bits of plans," Ms McManus said.

"I think that basically (Alan) Joyce has made the announcement of the 5000 jobs and has told the managers `you go find them'.

"Really bad decisions could happen because of this haste."

She said the union and Qantas would square off in the Fair Work Commission in Sydney on Thursday afternoon over the airline's plans to shed up to 90 full-time check-in staff at Sydney international airport.

"That's a hell of a lot of people as a percentage of that workforce," Ms Sullivan said.

She said the union had asked the commission to intervene after meetings between the union and Qantas stalled on Wednesday.

"We tried to bring up alternative ideas at this rushed meeting and they dismissed them," Ms McManus said.

Qantas said about 2500 workers would be asked if they wanted to take a voluntary redundancy, or in some cases, a part-time role.

"That doesn't mean that all 2500 people will go - the number that leave the business will be much less than that," a Qantas spokeswoman said in a statement.

"After employees have indicated if they want a voluntary redundancy we will review the applications and consult with those employees."

She said the impacted workers would "not be leaving within weeks".

"They will exit the business over April and early May," she added.