Former national security legislation monitor Bret Walker is warning tough new counter-terrorism laws are unlikely to ever be wound back.

The Foreign Fighters Bill passed this week makes it an offence to advocate terrorism, gives security agencies greater powers and gives the Federal Government the power to declare some overseas areas "no go" zones.

Prime Minister Tony Abbott has previously justified the new laws, saying the balance between freedom and security may have to shift, in light of the heightened terrorism risk.

But Mr Walker told 7:30 it was unlikely that balance will shift back.

"There's no history or reason to believe that this is an area where some brave government will propose removing these laws, particularly as they've been introduced under the banner of protecting us from things we would otherwise be unprotected from," Mr Walker said.

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"I don't see any reason to believe this is a temporary increase."

The former national security legislation watchdog said he was unconvinced many elements of the new counter-terrorism laws were needed.

"Now I don't accept the premise that many of these laws are necessary - I do accept the premise that quite a few of them are welcome and appropriate improvements to a system of laws which frankly is already as robust as any in the world," Mr Walker said.

"I don't see any reason to believe this is a temporary increase so as to decrease liberty in order to save it in the long run.

"Those trade-off notions are very dangerous."

Laws address national security, not copyright: Colvin

Meanwhile, Federal Police Commissioner Andrew Colvin has backtracked on his assertions the new counter-terrorism legislation could target people who illegally download movies and music.

The proposed new laws require telecommunications companies to store customer's phone, internet and email records for two years.

Commissioner Colvin has since clarified, and said the laws are designed to address national security and law enforcement matters, not copyright infringements.

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"Copyright breaches are civil wrongs and that's not what we're interested in," he told AM.

The Commissioner said it was "vitally important" police have access to metadata, as it is "one of the first tools we [the police] use in almost every investigation".

"It's fundamental to nearly all serious crime investigations," he said.

"It's very important that we can identify people who may be lurking on the internet, who may be trying to groom our kids. It's also important for national security investigations."

Commissioner Colvin said the laws are not giving police any new powers but will create consistency in the way telecommunication companies and internet providers store user data.

"I don't want to rely on luck when my investigators ask a telecommunications company for material, perhaps a company has kept it for seven years, or they haven't kept it at all," he said.

Critics have said the Data Retention Bill has been rushed and there are not enough privacy protections.

But Commissioner Colvin said user privacy was not being sacrificed under the new laws, as companies will only be retaining metadata, not user content.

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"This [metadata] is just identifiers to say person A spoke to person B, or a time of a connection to the internet. There's no content that we're looking to get through this process, it just simply identifiers," he said.

"There's a lot of discussion that we'll still have with industry to refine that and its pleasing to see a lot of industry have come out overnight supporting and saying that its good that the data set is quite refined so we'll still work through some of that.

"In terms of it being rushed, my real concern as the Police Commissioner, I know echoes the concerns of my colleagues around the country, is each and every day this material, this data is being degraded."