Internet users might soon be paying a “surveillance tax” under proposed laws forcing communications companies to store details of their customers’ traffic.

The Federal Government this week is expected to introduce legislation requiring communications companies to store customers’ metadata — the addresses and frequency of use but not the content of messages — for use by security agencies.

The so-called tax could mean an extra $120 a year on top of internet bills according to a calculation by iiNet, but others fear it will be much more.

The hike to internet bills will fund the detailed profile of your email traffic to be stored for two years.

The Government is concentrating on its “Foreign Fighters” legislation and other laws to pass with Labor’s backing.

But that bipartisanship could end with the metadata retention legislation.

Labor would be expected to amend it rather than reject it, but might put off its implementation until next year.

A group led by worried senators believe the legislation will be introduced Wednesday and a protest has been organised with the demand to “ stop data retention”.

Two cross bench senators, Nick Xenophon and David Leyonhjelm will join the Greens Scott Ludlam and civil liberties groups.

A key issue will be who pays for the storage and the running costs. Communication companies have absorbed the costs of data retention used by police but this proposal is much bigger.

It could cost $600 million to set up and a further $100 million a year to operate, according to calculations given to the former Labor government when it looked at the idea.

The cost of the scheme might increase were security organisations to ask for more details on messages — known as “scope creep” — or if individual Australians demand internet companies release details of their metadata stored.

The Communications Alliance, representing communications providers, is waiting to see the legislation which the Government has promised will be provided this year, but is ready to argue the storage requirements are out of proportion to the benefit.

The “vast majority” of metadata used by police to chase criminals is six months old or less,” Communications Alliance CEO John Stanton said.

“The Government has yet to put forward a rationale for wanting the sizeable impost presented by a requirement to keep all data for two years.

“A related and important issue is the fact that such a rich honeypot of data may be tempting for hackers and cyber-criminals.”