Some 79 laws are to be kept - mainly to protect information held on members of the public - in the biggest review of unnecessary secrecy undertaken for more than 20 years.

Yvette Cooper, the junior minister at the Lord Chancellor's Department, said the moves were the first stage of implementing the long delayed Freedom of Information Act, which will not come into force until 2005.

From Monday every government department and Whitehall agency will have to list on its website all the types of publications that are available to the public on demand.

The change will mean for the first time some ministries - notably the Department of International Development and the Lord Chancellor's Department - will publish the minutes of some of their top bodies and reports from advisers. Other bodies, including parliament and the Ministry of Defence, are still keeping the minutes of their top executives' meetings secret.

The decision to start to sweep aside secrecy is the subject of battles across Whitehall, with Lord Irvine, the lord chancellor, fighting the cause of openness against civil servants in other ministries trying to keep laws banning the release of information.

Sharing his sentiments are Alan Milburn, the health secretary, and Margaret Beckett, the environment secretary, who are planning to end the law making it a criminal offence to release commercial information on drugs and veterinary products.

A consultation paper will be issued next month repealing the ban on information held by both the medicines control agency and the veterinary medicines directorate.

The health and safety executive has also agreed to end a blanket ban on information held on major rail and factory accidents which could open the way to the public getting more details on some of the recent serious rail crashes such as those at Ladbroke Grove, Potters Bar and Hatfield.

Information kept secret will include personal details held on children with special needs, medical evidence on vaccine-damaged children, personal details held on child support claims, information held by MI5 and MI6, patent trade secrets and trade secrets on the composition of fertilisers and feedstuffs. The government will also maintain a ban on information held by the valuation office from personal visits to people's homes.

Still under review are how much information should be released on children involved in adoption procedures and on people who go to clinics treating sexually transmitted diseases. The Department of Health is keen to protect confidentiality in the area by a blanket ban on the release of information.

Other battles in Whitehall are taking place over whether to end laws banning the release of information collected by a large number of agencies and inspectors of private companies - from those who gather information on abattoirs to reports on dangerous electrical appliances.

Maurice Frankel, director of the Campaign for Freedom of Information, yesterday welcomed the government's move to repeal a large number of laws banning the release of information. But he was disappointed that many of the publication schemes did not take the opportunity to release new information.

He was also critical of the Ministry of Defence, claiming it was not taking a major step with the release of information on UFOs: "This was released by the MoD earlier after a successful request under the present code of access of information. All they are doing now is making it automatically available."

Information released will include:

· Papers on one of the country's most celebrated supposed UFO sightings near a joint RAF and USAF base in Rendlesham forest in Suffolk in 1980. The US released its papers on the sightings in 1983 under the American freedom of information act

· A quarterly report on whether Clare Short, international development secretary, is on target in spending overseas aid properly. The current report says Britain has failed to reach targets on cutting child mortality but is ahead of the game in nine African countries in getting boys and girls equal access to schooling

· From 2005 - details on the safety of medicines currently kept secret to protect drug companies