Australia plans to almost double its troop numbers in Afghanistan by next year amid warnings that the Taleban insurgency shows no sign of weakening.
Troops in Afghanistan are facing increasing threats of attack
Prime Minister John Howard said without an extra effort, the fight against the militants would not be won. He warned the country to prepare for casualties.
Six Canadian soldiers died at the weekend in the worst single incident for the Nato-led force since 2005.
Australia currently has some 550 soldiers in Afghanistan.
They are based at Tarin Kowt in Uruzgan province.
Mr Howard said the extra troops would include 300 special forces.
"We're not losing the war but we will not win it without renewed and increased effort," he said.
He also criticised those European countries which, while contributing troops, have placed a series of restrictions on the kind of activities their deployments can undertake.
Some of these caveats were lifted at a Nato conference late last year, but Germany, France and Italy will still only send their troops to trouble spots outside their patrol areas in an emergency.
Nato has more than 30,000 troops in Afghanistan, so in terms of overall numbers the additional Australian contingent may not look that significant, reports BBC world affairs correspondent Nick Childs.
But it is a major additional commitment for Australia - and it is the quality of the troops and what they are prepared to do in terms of combat that are seen by Nato as more important than the basic numbers, he adds.
The total Australian deployment in Afghanistan will reach approximately 950 by mid-2007, and will peak at about 1,000 in the middle of 2008, according to Mr Howard.
"We have done this against the background of a deterioration in the security environment in southern Afghanistan," he told a news conference.
He said the special forces commandos would be sent to Uruzgan province, where a smaller task force operated for a year until last September.
"Their role will be to enhance provincial security by disrupting Taleban command and control supply routes, and they will directly support the Australian reconstruction task force," Mr Howard said.
The area is in the south-east of Afghanistan, near the heart of the Taleban rebellion.
"I should make it clear that all of the intelligence advice suggests that there is a heightened security risk," Mr Howard said.
"There is the distinct possibility of casualties, and that should be understood and prepared for by the Australian public."
Other deployments will include air force radar crews in Kandahar, extra logistics and intelligence officers and an increased numbers of security personnel.
Last year saw the fiercest fighting in Afghanistan since coalition troops ousted the Taleban in 2001, with some 4,000 people believed to have been killed - about a quarter of them civilians.
The situation has been getting worse still in recent months.
The Taleban are maintaining strong opposition to Nato, particularly in the south and east. Helmand has been the focus of a recent operation by Isaf troops against militants.
Australia, a close US ally, was one of the first nations to commit troops to Afghanistan in late 2001, to join the US-led war to oust the Taleban and al-Qaeda.
Mr Howard's government has also sent about 1,500 troops to Iraq - a deployment which is fiercely opposed by the opposition Labor Party.
Labor has so far supported Australia's military involvement in Afghanistan.
Mr Howard said he had discussed the increased Afghan deployment with Afghan President Hamid Karzai and US commanders during his visit last month to Kabul.
LEAD INTERNATIONAL FORCES IN AFGHANISTAN
Locations refer to International Security Assistance Force (ISAF)
Total contributing nations: 37
ISAF total strength: Approx 35,500