Prime Minister Tony Abbott has revealed the cost of the Government's data retention plan could be almost $400 million a year, and has warned if it is not passed it would be a form of "unilateral disarmament" in the fight against crime.

The Government wants to force phone and internet companies to store data about calls and connections for two years to help authorities monitor suspected criminals and fight terrorism.

The legislation was introduced to Parliament last October and referred to Parliament's Joint Committee on Intelligence and Security, which is due to table its report next week.

There are concerns about how much the move will cost companies — and consumers — and how much the Government will contribute.

Mr Abbott today suggested that keeping the data would cost less than $400 million a year.

New data retention laws will: require telecos to keep customers' phone and computer metadata for two years

require telecos to keep customers' phone and computer metadata for two years keep information such as phone numbers, length of phone calls, email addresses and the time a message was sent

keep information such as phone numbers, length of phone calls, email addresses and the time a message was sent not keep the content of phone calls or emails, and explicitly exclude internet browsing

not keep the content of phone calls or emails, and explicitly exclude internet browsing give security agencies access to the data when they can make a case that it is "reasonably necessary" to an investigation

give security agencies access to the data when they can make a case that it is "reasonably necessary" to an investigation still require security agencies to obtain a warrant before accessing the actual content of messages or conversations

still require security agencies to obtain a warrant before accessing the actual content of messages or conversations seek to reduce the number of agencies able to access the data

seek to reduce the number of agencies able to access the data seek to limit access to stored communication such as text messages and emails

seek to limit access to stored communication such as text messages and emails introduce an independent oversight mechanism, allowing the Commonwealth ombudsman access to agency records in a bid to boost privacy protections

"There are a range of figures which have been taken to the joint standing committee, but even at the highest estimate it's less than 1 per cent of this $40 billion a year and growing sector," he said.

"It seems like a small price to pay to give ourselves the kind of safety and the kind of freedom that people in a country like Australia deserve."

Telstra has warned that the upfront costs of building new systems will be "significant" and wants taxpayer compensation.

Communications Alliance spokesman John Stanton said the industry was waiting to find out how much of the cost would be covered by taxpayers.

"It still amounts to a very significant cost and impost that needs to be paid," he told The World Today.

"The Government has so far said that it will make a reasonable contribution.. so there's a great deal of interest to see how much of the total burden the Government proposes to contribute."

Mr Abbott made his statement at the Gold Coast headquarters of the Bravehearts child protection organisation.

He warned there would be an "explosion in unsolved crimes" unless the legislation was passed.

"If we don't get it, it will be a form of unilateral disarmament in the face of criminals and the price of that is very, very high indeed," he said.