The SNP is calling for British government files on preparations for devolution to be released.
The papers relate to 1997 when ministers and officials were discussing the creation of a Scottish parliament.
The Scottish Government, which allows documents to be published after 15 years, says the information could be important in the run up to the vote on independence next year.
But the UK Government, which owns the files, has a longer time frame before publication and is scanning the paperwork to ensure it meets its information policy.
The Scotland Office, which deals with matters reserved to the Westminster parliament, said normal procedure is being followed.
SNP MSP Jamie Hepburn said the files "must be released".
He said: "It has been 15 years since devolution and whatever the UK Government is trying to hide it is time to be open with the people of Scotland. The Scotland Office will be cheating Scotland of its history if it does not allow these files to be released.
"We know Labour ministers including Blair and Brown were at odds over devolution, but that is no reason to hold that information back.
"It is vital that that in 2013 the year before Scotland's referendum on independence that the UK Government acts honestly and openly with the people of Scotland. The material in these files is not just an important part of our history it could be of importance to the current debate over independence."
The SNP has itself been criticised for its position on freedom of information. First Minister Alex Salmond was recently at the centre of a political row for trying to keep details about Scotland's place in the EU after independence under wraps. It was later revealed there was no specific advice from the European Commission to ministers in the first place.