Qantas will move heavy maintenance operations for its Boeing 717 fleet to Singapore, leaving 40 contractors in Canberra out of work.
The airline's Canberra hangar, which opened in 2015, will still be used for day-to-day maintenance of the aircraft by about 25 Qantas staff.
But Singapore-based ST Aerospace would take over the heavy maintenance of the planes, which is required for each plane every 18 months.
Qantas awarded the contract to ST Aerospace, which already services Qantas, Jetstar and Qantas Freight aircraft, from July 2019.
The initial four-year contract with Newcastle-based Korr Aviation is set to expire in April.
A spokeswoman for the airline said the majority of the maintenance on the Boeing 717 aircraft would continue in Canberra.
"Following a competitive tender process, ST Aerospace in Singapore, the world's largest provider of maintenance services, was awarded the contract for heavy maintenance on our Boeing 717 fleet," she said.
Korr Aviation would work to find other jobs for workers affected, a Qantas spokeswoman said.
The federal secretary of the Australian Licenced Aircraft Engineers Association, Steve Purvinas, said there was no consultation with workers and the contracted engineers would be "left high and dry".
"These aircraft never fly out of Australia, yet Qantas will intentionally send them empty to Asia to save a few bucks knowing that [the Civil Aviation Safety Authority] cannot properly audit work outside our shores," he said.
"This is another example of Qantas putting profit before safety."
Mr Purvinas said there was not enough work to sustain full-time employment for all of the Korr contractors but he said the union hoped Korr Aviation would pick up new contracts.
He also singled out Qantas chief executive Alan Joyce's remuneration package as an area the airline could make cuts to.
"In the last three years, Alan Joyce has earned $35 million personally. Yet 40 engineers sustaining 20 aircraft in the air have earned $12 million [in the same period]," he said.
"I think I know where cutbacks can be made."
A spokeswoman for Canberra Airport said it wouldn't be appropriate to comment on the contract as it was between two separate parties.