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 include efforts by the 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 since US whistleblower Edward Snowden leaked sensitive details of the NSA's spying program.

Mr Snowden, 29, a former CIA technical assistant, outed himself on Monday as the source of the leaks about the PRISM program, which taps into the data of the world's biggest technology firms including Google, Facebook and Apple.