Federal police are obtaining Australians' phone and internet records without warrants nearly 1000 times a week, it has emerged as controversy rages over a vast US surveillance program.

Revelations in a recent Senate estimates hearing also include efforts by Australian Federal Police to access Facebook and Google data of the kind gathered under the US National Security Agency's controversial Prism program.

The revelations draw Australia into the furious global debate about secret surveillance, which has erupted after US whistleblower Edward Snowden leaked sensitive details of the NSA's vast spying program.

The 29-year-old former CIA technical assistant has outed himself as the source of the leaks about the Prism program, which taps into the data of the world's biggest technology firms.

Experts and privacy advocates said on Monday that Australians' data would undoubtedly be among the vast tranches collected and monitored by the Prism program. And they have also raised questions as to whether Australia law-enforcement and intelligence agencies are receiving data from the American program.