The Taliban's takeover of Afghanistan has hamstrung investigators accessing evidence of alleged war crimes committed by Australian special forces soldiers.
Accessing people, evidence and places in the country is "extremely difficult, if not currently impossible", according to the head of the Office for Special Investigations.
But the 10 teams of investigators have been able to access evidence and leads outside of the country.
"My investigators are very experienced. I am very confident they will pursue all avenues," director general Chris Moraitis told a Senate estimates hearing on Monday.
"There are a variety of other sources we can investigate."
Mr Moraitis would not confirm if there were investigations into Australian Defence Force personnel beyond the original 19 individuals listed in the Brereton report, only confirming the report was within the office's remit.
It is too early to exonerate any of the 19 individuals at this stage, Mr Moraitis said.
The Brereton report alleged 39 Afghans were murdered by Australian special forces in 23 incidents.
It recommended the Chief of the Defence Force refer 36 matters to the Australian Federal Police for criminal investigation.
Australian Associated Press