The government does not know how many websites it operates, according to a report by the Committee of Public Accounts.
The number of government websites has rocketed to as many as 2,500, and the government spends around £208 million a year on internet services.
But more than a quarter of public sector bodies still do not know how much their sites cost, the report found. Of the organisations that could provide cost data, 40 percent merely offered estimates. And, only 16 percent have solid data about how well their sites are being used.
The government has embarked on a programme to rationalise its websites, by closing almost 1,000 "unnecessary sites", the report said. Agencies plan to move most citizen and business facing internet services to two websites, Direct.gov.uk and businesslink.gov.uk by 2011.
The government has identified 951 websites that could be closed. Alan Bishop, chief executive of the Central Office of Information, said: "Of those, 551, 56%, are already scheduled for closure. So far, there have only been 26 agreed exceptions out of the 951 and they are mainly for the single, departmental, corporate websites which will continue on into the future."
Committee chairman Edward Leigh told parliament: "The government's enthusiastic embrace of this new world of web-delivered services is not matched by a commensurate level of understanding of what it is achieving through its websites, how effective they are or whether they represent value for money."
Leigh added: "The time has long passed for getting a firm grip on the growth of government websites which has been almost uncontrolled."