FREEDOM of Information (FOI) campaigners have expressed concern over responses to requests being vetted at Stormont by ministers' special advisers.
In some executive departments responses to Freedom of Information (FOI) requests are only released after being approved by the special adviser (Spad).
FOI legislation was introduced in 2000 and gives people a right of access to an array of information held by public authorities.
Often used by campaigners and journalists, it has been used to expose issues including the MPs' expenses scandal and Prince Charles's lobbying letters to ministers.
Maurice Frankel, director of Campaign for Freedom of Information, warned Stormont against putting FOIs through an "explicitly political process".
"They run the risk of overstepping the line and being seen to be withholding information which ought to be disclosed," he said.
"They may be taking a risk by putting it through an explicitly political process, and the question is how are they using this process."
He added: "It shouldn't be necessary for ministers or special advisers to be examining responses before they are going out."
Almost 3,000 FOIs were sent to the executive in 2015. More than a quarter did not receive a response within the 20 working day deadline or had not been processed.
In June last year the Information Commissioner's Office (ICO) issued an enforcement notice to the finance department ordering it to answer all outstanding FOIs over six months old.
However, the ICO said the internal FOI process is a matter for individual public bodies.
"Freedom of Information law doesn't specify a sign-off process for FOI requests. It is up to individual organisations how they deal the internal process," a spokeswoman said.
"Organisations should be responding to requests within 20 days and using the correct exemptions, if any information is withheld."
Spads can each earn annual salaries stretching to more than £90,000.
Politically appointed but paid from the public purse like civil servants, Spads have been a source of controversy in the past over wages and accountability.
Stormont departments can have varying approaches, but it's understood some send all FOI responses to their private office for approval, with many being checked by Spads.
Each of the eight executive departments run by the DUP and Sinn Féin did not respond to requests for a comment.
Only the Department of Justice, headed by independent MLA Claire Sugden, outlined its FOI response process.
A spokesman said: "Responses are only forwarded to the ministerial/press office or Spad for their approval where it is felt they would be affected in some way by the public release of the information requested."
He added that FOI responses using the exemption 'prejudice to the effective conduct of public affairs' must be forwarded to the minister for approval.
