At present, public bodies must comply with requests costing no more than £600 to process. New proposals factor in additional processing costs, which would increase the likelihood of the upper limit being exceeded.
In a submission to the consultation, which closed last week, the advisory group recommended an exemption for registered charities and requests that are proven to be in the public interest.
It also wants anyone who submits a request to be given the option of paying the extra costs.
Lawrence Simanowitz, a charity lawyer at Bates, Wells & Braithwaite, said: "It's a fantastic tool for campaigning organisations to find out what the Government is doing, which is why they should be exempt from the proposals."