More than 500 personnel from the engineering department of Qantas Airways have been sacked as part of the company's restructuring operations.

Qantas, which made the announcement on Thursday, said the jobs involved 200 line maintenance jobs cut at its jet base at Sydney Airport, 250 contractors at Avalon Airport near Geelong in Victoria and 50 other jobs, including Richmond.

The ongoing job reductions, which started in May 2012, form part of the airline carrier's strategy of combining its heavy maintenance bases from two to one.

Lyell Strambi, Qantas Domestic chief executive, defended the job slashes, saying the airline's fleet of more modern aircraft had lessened the need for a large amount of maintenance people.

"Aviation is an extraordinarily competitive industry and we have the added pressures of the high Australian dollar and high costs relative to the rest of the world," he said in a statement.

"Our cost base in heavy maintenance is more than 30 per cent higher than our competitors, who do the vast majority of their maintenance overseas.

"We must close this gap to secure Qantas' future viability and this restructure will assist in making Qantas maintenance facilities in Australia more competitive."

The airline company, however, said 100 jobs will be added at its heavy maintenance base at Brisbane Airport.

Overall, Qantas reduced a total of 1,260 jobs from its engineering operations alone this year.

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