The cost of Australia's role in the American-led "war on terror" and its own precautions against attacks at home is climbing towards A$30 billion ($36 billion) amid growing doubts of its value.
The Government remains committed to military operations in Afghanistan that have so far cost more than A$6 billion and says the threat of terrorism continues to justify measures that have accelerated in the past decade.
These include an enormous beefing-up of counter-terrorism laws and agencies - the domestic Australian Secret Intelligence Organisation has trebled in size - and security measures ranging from transport and infrastructure to business.
In Afghanistan - a commitment longer than the nation's war in Vietnam and opposed by most Australians - the human and financial toll has been rising. Australia first entered combat in Afghanistan with the US-led invasion in 2001, mainly with Special Forces units that were withdrawn the next year as the emphasis moved towards reconstruction. Combat and reconstruction forces returned in 2005 and have increased to about 1500 troops committed to remain until at least 2014, when under present planning most will be withdrawn.
The war has killed 29 Diggers and injured 192.
Defence budget papers put spending on the war since 2001 at more than A$6 billion, rising from A$320 million in the first year of the conflict to a projected A$1.2 billion in 2011-12.
Australia has also spent about A$4 billion on military operations in Iraq and aid to both countries - with A$420 million allocated to aid in Afghanistan in the past three Budgets.
According to a book launched yesterday by Foreign Affairs Secretary and former ASIO chief Dennis Richardson, many of the claimed gains in Afghanistan will evaporate when foreign forces withdraw.
The book's editor, Professor Amin Saikal of the Australian National University's Centre for Arab and Islamic Studies, said it was unlikely the allies would leave behind a stable, secure and peaceful country.
"This is something the US-led coalition originally promised, but they will have enormous difficulty in achieving it by 2014 when they are scheduled to end their combat operations," he said.
Saikal said Australia had made some useful contributions to improving Afghanistan's infrastructure, security, education and health services but at a very high human and financial cost. The gains would also be reversible when Australia withdrew.
"It is easy for a power to get militarily involved in Afghanistan, but very difficult to disentangle itself from conflict with any degree of victory and vindicate its involvement in the first place. The US and its allies should have learned from their Vietnam experience and previous British and Soviet involvements in Afghanistan which had resulted in defeat."
The cost of Australia's "war on terror" has also been questioned by Mark Thomson, an expert on the defence budget with the Australian Strategic Policy Institute. He told Fairfax newspapers that Australia had spent an extra A$21.3 billion on defence and security since 2001, on top of what would normally have spent.
As well as Iraq and Afghanistan, a further A$10.4 billion had been directed to extra security at home, mainly on the federal police and ASIO. Thomson's estimates did not include spending by state and local governments, nor the cost of additional security introduced by business and other non-government organisations.
But Athol Yates, executive director of the Australian Security Research Centre, told Fairfax Australia had spent about A$10.5 billion on homeland security, which, with a further A$5.5 billion from state and local governments, and private industry, had pushed the total domestic security bill to about A$16 billion.
Although none of the more than 100 Australian victims of terrorism have been killed at home, the Government says the threat remains real.
Attorney-General Robert McClelland said four planned terrorist attacks had been foiled in Australia, and 38 people had been charged with terror-related offences.
ASIO director-general David Irvine told ABC radio: "I don't think we can be complacent and I don't think now ... is the time to relax our vigilance."