Australian diplomatic posts throughout Asia and the Pacific are spying on foreign governments through electronic intercepts that are fed into the vast intelligence network operated by the United States National Security Agency.
The latest revelations of Australian involvement have come from an NSA document leaked by American whistleblower Edward Snowden to the German publication Der Spiegel and supported by intelligence experts.
Previous leaks have claimed Australia has been eavesdropping on confidential telephone calls and electronic communications from neighbouring countries including Indonesia, Thailand and Malaysia.
Fairfax newspapers reported yesterday that radio, telecommunications and internet traffic was being intercepted by surveillance facilities hidden in embassies in Jakarta, Bangkok, Hanoi, Beijing and Dili, high commissions in Kuala Lumpur and Port Moresby, and other diplomatic posts.
Australian intelligence is fed into the global "Five Eyes" network linking Australia with the US, Britain, New Zealand and Canada.
The Australian Signals Directorate, the nation's key electronic intelligence-gatherer, has been a full intelligence partner with the US since 2004, granting Australia the highest level of co-operation available to a foreign agency.
The directorate is a full partner in the NSA's XKeystore programme, opening a huge pool of electronic data - including emails, search inquiries and online conversations - to intelligence analysts.
Australian data is collected and disseminated through the joint Australia-US base at Pine Gap near Alice Springs, the Shoal Bay Receiving Station near Darwin, the Kojarena satellite ground station near Geraldton in Western Australia, and the naval communications facility HMAS Harman near Canberra.
Australia and the US also share geospatial intelligence gathered by a satellite network.
New evidence that Australian embassies are also linked to the NSA's global electronic web has come from the document leaked by Snowden to Der Spiegel revealing an intercept programme operated from the diplomatic posts of the "Five Eyes" partners.
Fairfax reported that the document said facilities at Australian embassies were part of the programme codenamed "Stateroom", operated secretly by small staffs.
It said the facilities were covert, and their true mission was not known by most of the diplomatic staff at the various posts.
The document also said the intercept facilities were hidden, for example, in false architectural features or roof maintenance sheds.
An un-named former Australian Defence Intelligence officer told Fairfax the ASD conducted surveillance operations from Australian embassies across Asia and the Pacific.
The interception facility at the Jakarta Embassy collected intelligence on terrorist threats and people-smuggling, "but the main focus is political, diplomatic and economic intelligence", the former officer told Fairfax.
East Timor has also accused Australia of gathering sensitive data through electronic intercepts and bugging during negotiations on the large oil and gas reserves in the Timor Gap to the north of Australia.
Australian National University intelligence expert Desmond Ball told ABC TV Australia was monitoring the Asia Pacific region for the US through its diplomatic posts.
"Australia itself has used foreign embassies for listening purposes in an operation codenamed Reprieve ... in which we've used embassies in our region to monitor local, essentially microwave-relayed telephone conversations," he said.
"The fact that the United States has special collection elements that are doing this today is no different from what many other countries are doing today. It's not unusual."
Ball said it was important for Australia to know what its neighbours were thinking.
"You can't get into the information circuits and play information warfare successfully unless you're into the communications of the higher commands in the various countries in our neighbourhood."
Thomas Drake, a former NSA senior officer convicted of leaking confidential information, told the ABC the "Five Eyes" partners used one another's services to gather intelligence.
"I think what's particularly pernicious here is the fact we're actually listening on the personal communications of the highest levels of governments in countries that are supposed to be our allies ..."