Top secret documents leaked by former US intelligence contractor Edward Snowden are likely to reveal new details of Australia's support for deadly US drone strikes.

Meanwhile, human rights lawyers have called for a UN investigation of the killing by drones of two Australian citizens in Yemen last year.

Radar domes of the top-secret joint US-Australian missile defence base at Pine Gap near Alice Spring in central Australia. Credit:STF/AFP/Getty Images

The Melbourne-based Human Rights Law Centre has written to the UN Special Rapporteur on Counter Terrorism, Ben Emmerson, asking him to investigate the lawfulness of the military strike in Yemen that killed Townsville man Christopher Havard and Australia-New Zealand dual national Darryl Jones last November.

The Centre has also sought an investigation of the role of the Joint Defence Facility at Pine Gap near Alice Springs in supporting US drone strikes.