The last Australian troops withdrew from Oruzgan Province this week, but 400 will remain in Afghanistan next year, with defence planning for a similar-sized mission in 2015.
Commander of Australian forces in the Middle East Major General Craig Orme said the 2015 mission depended on the signing of the US-Afghanistan Bilateral Security Agreement (BSA) and the NATO status of forces agreement (SOFA).
"Our minister and the government has committed to the Resolute Support mission. It will be probably similar to our posture for 2014 and that will carry through," he told AAP on Wednesday.
"All of that is dependent on successful outcomes from the signing of the BSA and the NATO SOFA."
The US and Afghanistan have agreed on terms of the BSA, but Afghan President Hamid Karzai has refused to sign, saying that should be done by his successor, to be elected at the presidential election next April.
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The NATO mission in Afghanistan concludes at the end of 2014 and it has launched Resolute Support, a new mission to train and advise Afghan security forces post-2014.
The US, which envisaged keeping some 8000 troops in Afghanistan, says if the BSA isn't signed soon, it may have no choice but to plan for complete withdrawal. Without an agreement, it's unlikely Australia will stay.
Under current plans, Australian troops will remain to mentor instructors at the Afghan National Army (ANA) Officer Academy in Kabul and at the ANA 205 Corps headquarters in Kandahar.
As well, Australians will continue to advise the ANA on logistics, while a small number of special forces will advise Afghan police special forces headquarters.
A RAAF detachment operating two Heron unmanned surveillance aircraft will remain until mid-year.
Because of the risk of insider attack, Australian units working close to Afghan forces have their own security forces.
General Orme said Afghanistan remained a dangerous place.
"We are still concerned about the risks our people face. We are still concerned about the challenges we need to be up for. I am concerned that we continue to get the support that we need to do the mission that we still have in Afghanistan and across the Middle East," he said.
The last 150 Australian troops flew out of Oruzgan aboard of pair of RAAF C-17 transport aircraft. That included special forces, the first Australians into Oruzgan in 2005 and among the last out.
General Orme said the vast majority would be home by Christmas.
