Qantas Airways Ltd., Australia’s largest carrier expects to lose as much as A$300 million ($271 million) in the six months ending in December after a “marked deterioration” in conditions and plans to cut as many as 1,000 jobs. Its shares fell the most in 18 months.

Rising fuel costs and a fall in ticket prices amid an increasing supply of airline seats will drive the company to lose between A$250 million and A$300 million in the first half before tax and one-time items, the Sydney-based company said in a regulatory statement.

Qantas has called for support from Australia’s government amid rising competition from second-ranked Virgin Australia Holdings Ltd., which is raising cash by selling new shares to fund its attempts to take market share. Qantas will also review its capital spending plans and look for other ways to raise cash, according to the statement.

“We will continue to take the fight to the competition and strengthen our leading position in the domestic market,” Chief Executive Officer Alan Joyce said in the statement.