The UK government has admitted it will have only a partial set of email interception rules in place by its 2 October deadline.

It had set the deadline to ensure compliance with the Human Rights Act, which becomes law on that date, and to head off possible challenges in the European Court of Human Rights to the way that the government monitors communications.

The Department of Trade and Industry (DTI) said yesterday that it had extended the consultation process on lawful business practice to end confusion over what powers companies have to intercept internal emails.

Although the vast majority of the much criticised Regulation of Investigatory Powers (RIP) Act will be enacted on 2 October, the section relating to internal email monitoring will not now become law until 24 October.

Fears had been expressed that employers, particularly in the public sector, could be sued for breaching employee privacy rights set out in the three-week grey area before the delayed section of the RIP Act becomes law.

The DTI confirmed earlier this week that, under the Act, firms are entitled to intercept staff communications when they are ill or on holiday, as long as the employee has given their permission. Business groups had criticised the need to obtain consent to monitor emails.

A DTI spokesman said that allowing firms to monitor staff email had always been the intention, despite weekend press reports of a climb down on the issue. "The Act allows interception where the interceptor has reasonable grounds to believe both the sender and the recipient have consented," he said.

A Home Office spokesman later added that a letter had been sent to public authorities outlining the procedures they should follow between 2 October and 24 October.

The Confederation of British Industry said it had asked for clarification of the issue, and would welcome this confirmation.

Security experts have said companies should include the right to intercept email in employee handbooks signed when an employee joins an organisation.

Caspar Bowden, director of think tank the Foundation for Internet Policy Research, said the government had itself to blame for the delay by only allowing four weeks for consultation - half of the period usually made available.

"You can't really blame people for acting like headless chickens given the ridiculously foreshortened consultation period," he said.