New Zealand could potentially face an international war crimes case over allegations Kiwi SAS troops were involved in the killing of civilians in Afghanistan, an international law expert says.
Allegations six civilians were killed and 15 were injured during a raid north of Kabul have been made in a book by investigative journalist Nicky Hager and war correspondent Jon Stephenson.
Hit and Run, released on Tuesday, claims SAS soldiers led the operation in revenge attack for the death of regular New Zealand soldier, Lieutenant Tim O'Donnell, earlier that month.
New York University adjunct law professor Alison Cole on Wednesday told Radio NZ the book could be used as evidence by prosecutors at the International Criminal Court, who were at a "crucial" point in deciding whether to open an investigation into the Afghanistan war.
"The standard of proof at this stage in proceedings at the International Criminal Court is reasonable grounds to believe. That is relatively low," she said.
"If you look at the history of arrest warrants issued by the international criminal court, they're usually based on open source material and usually done by human rights groups. They look very much like the report that was launched yesterday."
She said the burden would then be put on the New Zealand government to show it was willing and able to run, or had run, its own full investigation into the matter.
"The prosecutor could very well be looking at this right now."
Former defence minister Jonathan Coleman on Wednesday said New Zealand soldiers did not kill any civilians, but could not rule out other nations' forces did.
Professor Cole said an investigation would have to look at the chain of command and whether "the New Zealand military prevented or punished what they knew - or should have known - was happening".