SYDNEY (REUTERS) - Australia's new conservative government will introduce legislation to raise its debt ceiling to A$500 billion (S$599.7 billion) from A$300 billion to head off concerns the country could reach its limit before Christmas, Treasurer Joe Hockey said on Tuesday.

In a budget update before September's election, Australia's Treasury forecast the face value of outstanding Australian government securities would reach its A$300 billion limit by December 2013 before falling back to around A$290 billion by June 30, 2014.

Parliament is expected to hold its first sittings under conservative Prime Minister Tony Abbott in late October, giving the new government up to six weeks to pass the new debt limit.

Hockey also announced plans for a Commission of Audit to report on the scope, efficiency and functions of the government.