Australia said Tuesday it will bring its troops home from Afghanistan a year earlier than planned with most soldiers withdrawn in 2013 after significant security gains over the past 18 months.

Canberra, a key coalition ally of the United States, has repeatedly said it intends to remain in the war-wracked nation until 2014 but Prime Minister Julia Gillard said Afghans would now be ready to take responsibility earlier.

She will take her pull-out timetable to a NATO summit in Chicago next month with her announcement coming a day ahead of NATO foreign and defence ministers meeting in Brussels to fine-tune their own troop withdrawals.

"I'm now confident that Chicago will recognise mid-2013 as a key milestone in the international strategy," she said in a keynote speech shortly after a wave of coordinated Taliban attacks in Afghanistan left 51 people dead.

"A crucial point when the international forces will be able to move to a supporting role across all of Afghanistan."

Australia has some 1,550 troops stationed in the strife-torn country and has so far lost 32 soldiers in the conflict.

Gillard said they would begin leaving as soon as Afghan President Hamid Karzai declared Afghans would take responsibility for Uruzgan province, where most Australian forces are based.

Karzai is expected to make the announcement "in the coming months" and once he did, the withdrawal should take 12 to 18 months.

"And when this is complete, Australia's commitment in Afghanistan will look very different to that we have today," she said.

"We will have completed our training and mentoring mission with the 4th Brigade.

"We will no longer be conducting routine frontline operations with the Afghan National Security Forces. The Australian-led Provincial Reconstruction Team will have completed its work.

"And the majority of our troops will have returned home."

While most soldiers will return, she made clear Australia stood ready to "provide niche training to the Afghan National Security Forces after 2014".

"We are prepared to consider a limited Special Forces contribution -- in the right circumstances and under the right mandate," she said.

Canberra has faced increasing pressure over the long-running Afghan campaign and a 2013 pull-out will be a year in advance of the 2014 deadline previously laid down by NATO-led international forces.

It will also mean most Australian troops are likely to be home before the next election.

Gillard is struggling in the polls and many people oppose the deployment to Afghanistan, but she denied it was a political decision, or had been accelerated because US President Barack Obama faces an election in November.

"What drives the timetable is the assessment by ISAF and then by the Afghan government of the right moment to enter transition," she said, referring to the NATO-led International Security Assistance Force.

"And that is based on an assessment of the growing capacity of the Afghan national security forces."

Australia's Afghan deployment began in 2001 before Canberra pulled out, only to redeploy to the arena in 2005.

Gillard said while the challenges remained significant, important gains had been made that helped fast-track a transition to full Afghan security responsibility.

"Bin Laden is dead. Most of Al-Qaeda's senior leaders have been killed or captured. We have pushed Al-Qaeda's remaining leaders to the Afghanistan-Pakistan border area," she said.

"The Afghan National Army's 4th Brigade is increasingly capable of planning and conducting operations on its own and the Afghan security presence across the province is expanding."