The Council on Tribunals has attacked provisions in the 1996 Housing Act to charge fees to users of Leasehold Valuation Tribunals.
The valuation tribunals have been given the task of strengthening the rights of owners of leasehold flats in their dealings with freeholder landlords under the Act.
But in its annual report the Council on Tribunals, which is responsible for monitoring tribunals, argues that the £500 fee to use the tribunals goes against the tribunals' ethos of administering quick and inexpensive justice.
John Saunders, secretary to the council, said the move represented a "worrying addition to the small number of tribunals that do charge a fee and there is a risk that people will not fully exercise their rights because of the costs.
"Leaseholders will have to think very carefully before they go to a tribunal. County courts were a substantially less expensive solution when there was a possibility of legal aid, but this route is now blocked".
Saunders suggested the move might create a precedent, opening the door for other tribunals to implement similar charges in the future.
James Driscoll, consultant solicitor with Trowers & Hamlin and author of a guide to the Housing Act, said groups of well-resourced flat owners would not find it difficult to pay the charge, but it would hit low income groups and the elderly.
"The irony is that the tribunals are less accessible than county courts, which defeats the original object of the tribunals," he said.
He warned that tribunals were suffering from a lack of resources and pointed out that delays already plagued the system.
"Waiting for a hearing date can take up to six months in the London area and a decision can take several more months to reach, so the idea of tribunals as quick and effective is already flawed."