The Australian government was aware of the US National Security Agency's top-secret Prism program at least two months before the Guardian revealed its existence to the world.

A freedom of information request by the ABC has confirmed officials in the Attorney General's Department prepared a secret briefing for the minister on Prism in March 2013, more than two months before the first story was published revealing the electronic surveillance and data mining program undertaken covertly by US agencies.

The ABC's FoI request has confirmed that a protected brief was prepared for the Australian attorney general on Prism on 21 March 2013. That document was withheld from release by the Attorney General's Department on national security grounds.

The broadcaster was given access to three other documents related to Prism. Large chunks of the documents were redacted, including sections of talking points prepared for ministers and officials about what effect Prism would have on the privacy of Australians, and an analysis of media reporting on the issue.

Australians remain none the wiser about how data collected under the NSA program is used by intelligence agencies here.

The Greens senator Scott Ludlam and the South Australian senator Nick Xenophon pursued Labor frontbenchers before the election about what the Australian government knew about Prism.

Xenophon was particularly concerned to learn whether Australian parliamentarians were being watched by intelligence agencies. But there were no clear answers.

Ludlam asked questions on notice in the Senate about Prism and Australia's knowledge of the controversial program, which were released again as part of the ABC's FoI request. Senator Joe Ludwig responded to the questions on behalf of the attorney general, Mark Dreyfus.

Ludwig told Ludlam that all communications interception activities in Australia undertaken by agencies were carried out in accordance with Australian law, and the government did not comment on the law enforcement or intelligence capabilities of other governments.

Ludlam said on Tuesday: "The Australian government has tried to be completely opaque about this. And what we find are attorneys general, either of the Labor or the Liberal variety, will just wave their hands and say 'national security', and that's meant to make you stop asking questions."

Ludlam seems to have lost in his bid for re-election to the Senate in the 2013 election. He has sought a recount of the votes in Western Australia and will find out midweek if this request has been successful.