Acting Victorian Privacy Commissioner, Anthony Bendall, has slammed the federal government's proposed two-year Web and telecommunications data retention laws as "characteristic of a police state".

In a submission to the Joint Parliamentary Committee on Intelligence and Security on the Inquiry into potential reforms of the National Security Legislation, Bendall said the proposal, which could see internet service providers (ISPs) retain customer data for two years and allow law enforcement agencies to access a person's computer to get to a suspect's device, were "completely unjustified".

"To access a third party's computer which has no connection with the target is extraordinarily broad and intrusive," read the submission.

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Read: Data retention proposals put on hold?

"These are powers usually characteristic of a police state. Adversely impacting the privacy of an individual [the third party] should only be permitted in the most extreme circumstances as a last resort when all other methods have been exhausted."

Bendall's submission went on to say that the power to alter, rather than access, a third party computer should not be permitted.

He added that while national security was in the public interest, privacy rights needed to be preserved.

"Most security operations -- such as searches, interceptions or warrants -- are by their nature privacy invasive," read the submission.

"Any extension of such invasions requires careful scrutiny and deliberation."

According to Bendall, since 2001, the enactment of multiple terrorism laws such as the US Patriot Act has progressively stripped away many civil rights formerly built up under the common law for hundreds of years.

He added that preserving the right to privacy was essential to maintaining a democratic and free society.

According to Bendall, where the state sought to encroach into privacy and other civil liberties through the exercise of intrusive powers, such powers should be:

Exercised for legitimate purposes and not for improper reasons

Used only when necessary and not arbitrarily or without reasonable cause

Carried out in a way proportionate to their need and not in a manner that is excessively intrusive or to an extent that is overly broad

Shown to be effective in achieving their legitimate aims, with appropriate transparency in reporting outcomes.

Bendall is not the only government figure to speak out against the proposed data retention laws. Greens Senator Scott Ludlam has called the proposal a "dodgy premise" and said the federal government has not seriously considered the privacy implications of the proposals.