Scottish Liberal Democrats have accused the nationalist government of using freedom of information laws as a barrier in the referendum debate.
The accusation came as a request to ministers for crucial information on their independence plans lay unanswered fewer than 50 days before Scots go to the polls in September.
Speaking ahead of the Scottish Parliament’s beginning its final session before the referendum, Mr Rennie said that SNP ministers were now in the last chance saloon to honour the open debate they have long promised voters.
If the SNP use the freedom of information process available to them, voters may not be entitled to see information nationalists ministers have tried to bury until after the referendum.
Mr Rennie said:
"At the start of June I used freedom of information laws to force the nationalist government to reveal its workings on set up cost. We have now entered the to-and-fro process of reviews, and liaison with the information commissioner. If the nationalists use every rule and timeframe to their advantage they could feasibly get away with not publishing this until after the referendum.
"Far from the open and democratic debate we were promised the SNP government is using freedom of information laws as a barrier. I'm grateful that the information commisioner has said she is willing to expedite requests for information before the referendum but it shouldn't have to come to that.
"With fewer than 50 days until the referendum Alex Salmond is now in the last chance saloon to honour the open debate he has long promised voters. I know that we are not the only people looking for answers and I would urge anyone with freedom of information requests to the Scottish Government on key independence issues such as currency and pensions to take the information commissioner up on her offer."