Australia's electronic spy agency is using the nation's embassies to intercept phone calls and internet data in neighbouring countries, according to new information disclosed by intelligence whistleblower Edward Snowden and a former Australian intelligence officer.

The secret Defence Signals Directorate operates clandestine surveillance facilities at embassies without the knowledge of most Australian diplomats.

Fairfax Media has been told that signals intelligence collection occurs from Australian embassies in Jakarta, Bangkok, Hanoi, Beijing and Dili, the high commissions in Kuala Lumpur and Port Moresby and other diplomatic posts.

A secret US National Security Agency document leaked by Mr Snowden and published by Germany's Der Speigel magazine reveals a highly sensitive signals intelligence collection program conducted from US embassies and consulates and from the diplomatic missions of other "Five Eyes" intelligence partners, including Australia, Britain and Canada.