Bring troops home, Greens say

The deaths of two Australian soldiers have sparked debate over the future of the mission in Afghanistan, with Australian Greens leader Bob Brown calling for the return of troops by the end of the year following a review.

Two as yet unnamed diggers, aged 25 and 27, were killed in Afghanistan overnight in separate incidents.

The first involved an Afghan National Army soldier fatally shooting his Australian comrade numerous times before running away.

In the second an army lieutenant died after the Chinook helicopter he was in crashed while on a resupply mission.

Senator Brown said it was time for a "stocktake" and the government should consider empowering the parliament to approve the deployment and return of troops.

"We should bring our troops home safely to our shore to be better deployed in Australia's interests," he told reporters in Canberra, passing on his condolences to the families and admiration for the "courage and commitment" of ADF personnel.

Prime Minister Julia Gillard said Australia had a strong and professional relationship with the ANA.

"We have trained and mentored hundreds and hundreds of Fourth Brigade soldiers," she told reporters in Canberra.

"We partner with them in patrols throughout Oruzgan province and they are becoming a more capable and professional force.

"This work is vital to our mission in Afghanistan, indeed we cannot succeed in that mission without doing this training."

Ms Gillard wouldn't be drawn on whether the death penalty should be imposed on the ANA perpetrator if he was caught.

"Let's deal with this one step at a time here," she said.

The initial death is the latest in a string of incidents in the past two months of Afghan soldiers and police, or Taliban dressed as such, killing coalition forces.

In late April, eight American soldiers and a US contractor were shot dead by an Afghan air force pilot after a row at a NATO training centre for the national air force in Kabul.

The Taliban claimed responsibility for the incident, but Afghan officials could not confirm if it was an insurgent attack.

Taliban fighters dressed in military and police uniforms also struck several high-profile targets, including the department of defence, and two NATO soldiers were shot dead by an Afghan border police officer in early April.

"This incident is obviously going to quite rightly raise some very serious questions about the security measures we have in place," defence force chief Angus Houston said.