The decision to keep secret the full legal advice given to Tony Blair in the run-up to the Iraq war has been defended by Lord Falconer.
There are exemptions to what information has to be released
Despite new freedom of information laws coming into force, the lord chancellor said it was "only right" for ministers to be able to seek advice.
Media groups want to use the law to unveil Attorney-General Lord Goldsmith's advice.
But ministers are likely to argue such information is exempt from the rules.
The Freedom of Information Act was passed four years ago but has only just become law.
It will give people the right to see information held by 100,000 public bodies, including the government, police forces, hospitals, schools and local councils.
'Space for advice'
A summary of Lord Goldsmith's verdict on the legality of the war has been published.
But media organisations and anti-war campaigners want to see the detailed arguments he used to justify the advice.
Their efforts to obtain the documents have so far been thwarted but new requests are now being filed.
Questioned on the issue during a visit to Bingley, west Yorkshire, Lord Falconer said: "Whether
or not information is disclosed depends on the act, but every government needs
space to take advice.
"I don't think any government with an act such as this
would act on any other basis."
Information exempt from the act includes "the provision of advice by any of the law officers" - which would include Lord Goldsmith.
However, this exemption is subject to a test of whether it is in the public interest to withhold the information.
Lord Falconer dismissed suggestions that the government was being selective in
the documents it chose to release
"The reason it is not
selective is it can be tested and appeals can be made to the information
commissioner, who acts independently of government," he said.
"A tribunal would then
determine whether they should be released."
Lord Falconer argued the ministers would only use their veto on the information commissioner's decision rarely - and with the full support of the Cabinet.