CANBERRA - Australia will send an additional 450 troops to Afghanistan to fight a war that is beginning to lose public support and which Prime Minister Kevin Rudd has conceded is being lost.

Rudd has also accepted the inevitability that more Australians will be killed and that there is no deadline for withdrawal, but remains committed to a campaign he believes is necessary to defeat terrorism.

"We must not allow Afghanistan to once again become the unimpeded training ground and operating base for global terrorist activity," he said yesterday.

The decision to send more troops came after Rudd spoke to US President Barak Obama last week, and despite Canberra's concern at the conduct of the war. It follows an increase in US forces from 38,000 to almost 60,000, and agreement for increased commitments from Nato nations including Britain, France, Germany and Italy.

Rudd said it was clear the present allied strategy was not working, a view increasingly shared by Australians who in a new Australian National University poll supported the war by a narrow majority of 53 per cent.

"A significant minority remain opposed," the poll said. "That opposition is likely to increase if Western military intervention in Afghanistan does not bring tangible gains.

Rudd said he was prepared for this: "I accept that for the reality that it is."

Rudd also said more Australians were likely to die.

"As I make these further commitments today, I am acutely conscious of the fact that I am placing more Australians in harm's way, and I fear that more Australians will lose their lives in the fight that lies ahead."

The ANU poll also said Australians were very pessimistic about the prospects of success in the war. Only 17 per cent believed the US-led alliance was winning, while 69 per cent said the West was losing.

Rudd, who has been critical of European support in Afghanistan and has repeatedly declared there is "no blank cheque" for continued Australian participation, said Canberra agreed with America's assessment that the present strategy was not working.

"If anything, security in Afghanistan is deteriorating."

But he said Obama had prepared a new US action plan, both civilian and military, aimed at redefining the mission in Afghanistan and outlining a new strategy, and the allies had last month charted a new way forward at a meeting in The Hague.

This concurred with Australia's definition of its mission in Afghanistan, including the strategic denial of Afghanistan as a training ground and operating base for global terrorist organisations, stabilisation of the Afghan state through a combination of military, police and civilian effort, and training Afghan security forces.

Rudd said Australia would not bow to the threat of terrorism from Afghanistan