People in Scotland are not convinced that public bodies have become more open despite freedom of information legislation, it has been claimed.
Mr Dunion said people in Scotland see the Act as a powerful tool
Scottish Information Commissioner Kevin Dunion spoke out after a new poll found a drop in the number of people who said public bodies were more transparent.
A study undertaken for the commissioner found scepticism over whether there had been a culture change in public bodies.
However, two-thirds of people said more data was available than before the law.
The survey of 1,000 people, carried out last month, revealed that 60% believed organisations were becoming more open and accountable, compared to 67% in a previous study.
It also found that 76% of those who have made requests since the Freedom of Information Act came into force in 2005 had received all or some of the information requested.
Mr Dunion said: "The Scottish public recognise that the Freedom of Information Act is a powerful tool and the indications are that they are seeing the benefits of it.
"People are confident that more information will come into the public domain as a result and fewer believe public authorities can get round the act.
"However people still remain to be convinced that Scottish public authorities are changing culture to become more open and accountable."
The research has been published on the same day as a major conference on freedom of information is held in Edinburgh.
In his keynote speech, the commissioner will review the experience of the first two years of the act's operation.
He will highlight the success of the legislation so far, arguing it has made available information which would never previously have been released into the public domain.