The Afghanistan province where Australian troops were stationed for eight years and suffered most of their casualties is in danger of sliding back into Taliban control, Afghan sources and experts say.

Eighteen months after Australian Defence Force troops withdrew from their main base in Oruzgan province, a power vacuum left by the assassination of a Western-backed strongman has sparked an insurgency push that by some estimates has put half the province in Taliban hands.

Safety and security: The deterioration in Oruzgan province appears to put at risk gains made during the nearly eight years that the ADF were stationed there. Credit:Sergeant Neil Ruskin

Afghanistan's ambassador to Australia, Nasir Ahmad Andisha, confirmed there have been setbacks, saying: "It's unfortunately the case that the level of attacks, the intensity and the sophistication, is something we have not seen in the last four or five years."

He denied that insurgents were controlling entire districts but acknowledged "they are trying to show that they can take over some of the districts".