The Campaign for Freedom of Information in Scotland (CFoIS) has called on the government to make sure all public services are covered by the law - and not just some as at present.
The CFoIS also wants a planned royal exemption from FoI law to be dropped.
Campaign co-convenor Carole Ewart welcomed a parliamentary report which has recommended the plugging of loopholes in the Scottish government's latest freedom of information legislation.
Carole Ewart said: "A 'purpose' clause should be added to make it clear that all public services should be covered by the law, and the new absolute exemption proposed for royal communications should be dropped."
An increasing number of public services are being moved outwith the scope of freedom of information legislation via private contractors, housing associations, arm's-length organisations and voluntary bodies.