Titled Sri Lanka's Killing Fields, Jon Snow presents the investigation which was shown to the United Nations Human Rights Council on Friday.
Disturbing footage in the film includes the apparent extra-judicial massacre of prisoners by government forces, the aftermath of targeted shelling of civilian hospitals and the bodies of female Tamil fighters who appear to have been sexually assaulted.
Also examined in the film are atrocities carried out by the Tamil Tigers, including the use of human shields, and footage depicting the aftermath of a suicide bombing in a government centre for the displaced.
The UN screening was attended by a number of ambassadors from nations including the US and UK.
A special investigation by Channel 4 into war crimes in Sri Lanka is screened at the UN.