Qantas is expected to announce it is shedding more than 400 jobs in its engineering department as it closes down its heavy maintenance base at Tullamarine Airport.
News Ltd newspapers say negotiations with the Victorian government could not save the jobs and an announcement could be made as early as Monday.
News Ltd says a second Victorian facility at Avalon, near Geelong, will remain open for the meantime.
Avalon is home to 660 heavy maintenance workers who are halfway through upgrading the interiors of Boeing 747 jumbos to the standard of Airbus A380 superjumbos.
Work on Boeing 737 aircraft at Tullamarine is expected to be shifted to Brisbane to join Airbus A330 work already done there.
Qantas has stated previously that it expects to shed about 60 per cent of its heavy maintenance workforce over the next five to seven years as it consolidates to a single base.