Qantas is to close a heavy maintenance base at Avalon in Victoria next year.
The airline confirmed on Friday that the plant, which maintains its ageing fleet of Boeing 747s, will close by the end of March.
It said 53 employees and 246 contractors would be affected.
Qantas is moving away from Boeings, towards Airbus aircraft.
"We're gradually retiring our 747 aircraft, which means there's just not enough work to keep the base at Avalon viable and productive," Qantas Australia chief executive Lyell Strambi said.
The ABC reports 250 personnel were made redundant at Avalon earlier this year. Operations at the base began in May 1998.