Federal police boss Reece Kershaw is confident about the progress of a probe into Australian troops' alleged war crimes in Taliban-occupied Afghanistan.
Neighbouring countries are being used by investigators to help probe possible war crimes in the war-torn country back under Taliban control.
"These are long investigations - very complex," the AFP commissioner told reporters in Canberra on Monday.
"We'll make sure that, whatever happens, there's a brief of evidence to go forward to (the Director of Public Prosecutions). That will occur."
It has been a year since a report into credible evidence of war crimes and the unlawful killing of 39 Afghan nationals was unveiled.
Inspector-General of the Australian Defence Force Paul Brereton identified 25 current or former personnel accused of perpetrating one or more war crimes.
An Office of the Special Investigator was established to assess allegations in the report.
Progress was hampered by the Taliban's takeover of Afghanistan in August following two decades of occupation by western forces.
""It's about access at this stage," Mr Kershaw said.
"We've been able to deal with matters using nearby countries on occasion ... whether it be Pakistan or somewhere else nearby.
"There'll be different methods that will be used to contact those witnesses and manage them."