The Australian Defence Force (ADF) has released findings from a four-year inquiry into misconduct by its forces.
The inquiry investigated 57 incidents and heard from hundreds of witnesses.
It had uncovered a "shameful record" of a "warrior culture" by some soldiers, ADF chief General Angus Campbell said.
He said the report said 25 Special Air Service (SAS) soldiers were involved in the killings, none of which could be "described as being in the heat of battle".
"None were alleged to have occurred in circumstances in which the intent of the perpetrator was unclear, confused or mistaken," Gen Campbell said.
"And every person spoken to by the inquiry thoroughly understood the law of armed conflict and the rules of engagement under which they operated."
Prime Minister Scott Morrison had phoned Afghanistan's President Ashraf Ghani to express his "deepest sorrow" over the findings, the president's office said.
Mr Ghani said he had been assured that Australia was committed to "ensuring justice".
The inquiry - by the Inspector-General of the ADF - was conducted behind closed doors, meaning few details have been reported until now. The inquiry did not have the power to lay criminal charges.
Last week, Mr Morrison warned the report would bring "difficult and hard news for Australians".
He said a special investigator would be appointed to consider prosecutions from information contained in the report.
An independent oversight panel would also be established to provide "accountability and transparency that sits outside of the ADF chain of command", the government said.
Australia maintains an operation of around 400 soldiers in Afghanistan as part ongoing peacekeeping efforts with the US and other allies.