Freedom of information laws are to be extended as part of a push by the Liberal Democrat leader, Nick Clegg, to make public bodies more accountable.

The deputy prime minister also wants to cut the length of time government records are kept secret from 30 years to 20.

Current FoI legislation covers councils and government departments, but Clegg wants it to include potentially hundreds more bodies such as the Association of Chief Police Officers, the Financial Services Ombudsman and the Universities and Colleges Admissions Service.

In a speech tomorrow, Clegg will say the reforms are "part of our wider project to resettle the relationship between people and government".

"Free citizens must be able to hold big institutions and powerful individuals to account," he will say.

"And not only the government. There are a whole range of organisations who benefit from public money and whose activities have a profound impact on the public good.

"In order to do so, citizens must first know what goes on in these institutions. And they must be at liberty to speak out about the things they discover. It is a modern right to information combined with traditional freedom of expression."

Clegg will say progress was made under Labour but this had "stalled". There are too many exemptions to the FoI Act, while information is often placed "behind tedious bureaucratic hurdles", he will say.

Clegg will add: "We still live in a society where information is hoarded by the few. And, as we know, information is knowledge, and knowledge is power.

"It is a fundamental right of all citizens to be able to hold their government to account. The coalition government is committed to making this the most open government ever.

"We want to make it easy for people to find out information that is relevant to them, to ensure that public bodies are acting in the public interest and providing good value for money.

"The goal is the greater transparency we desire and the public deserves."

Plans to cut the 30-year rule on government secrets will be phased in over 10 years from 1 January 2013. It will include government briefings, policy documents and emails between ministers.

The changes follow the recommendations of the Dacre review, commissioned by the last government, which said the restrictions should be reduced to 15 years.

The last government introduced the legislation to reduce the 30-year rule to 20 years but it was never enacted.

Adding more public bodies to the FOI Act would require secondary legislation, something Clegg hopes can be brought in by the end of the year.

The Acpo president, Sir Hugh Orde, welcomed the proposals.

He said: "Any organisation that operates as part of a key public service should be accountable and open to public scrutiny.

"The Association of Chief Police Officers has been asking to be included under the act and welcomes the extension of authorities that it offers."

Daniel Hamilton, campaign director of the group Big Brother Watch, also welcomed Clegg's announcement.

He said: "This is a very welcome step towards increasing transparency in government.

"Members of the public have a right to obtain information without being frustrated by bureaucracy and red tape. What have those opposing this move got to hide?"

A spokesman for Ucas said he did not wish to comment at this time.