The Legal Ombudsman remains uncertain about demand relating to claims management companies, just weeks before it starts taking complaints about them.
The LeO business plan for 2015/16 reveals specific risks surrounding the extension of its jurisdiction from the end of January.
The plan forecasts an extra 3,000 cases, although there is still a 'relative lack of information' about the nature of the demand and what impact that may have on cost and performance.
The extension of the ombudsman's powers has been in the pipeline since August 2012 and its estimated £2.9m cost is being met by the CMCs.
The plan also states that the ombudsman is working toward accepting complaints about accountants registered with the Institute of Chartered Accountants in England & Wales for probate work. The ICAEW became an approved regulator for alternative business structures earlier this year.
The cost of handling legal complaints is again expected to fall - partly because the number of complaints is forecast to dip as low as 7,400. Estimates for previous years have anticipated as many as 8,500 complaints.
The budget for 2015/16 is set at £11.5m, a 13% reduction on the £13.2m budget for 2013/14.
The ombudsman service said it will continue to work on establishing a voluntary scheme that providers of unregulated legal services can choose to join.
Steve Green, chair of the Office of Legal Complaints, said consumers do not currently make a decision about purchasing a legal service based on whether that provider is regulated - but they still expect to be able to seek redress for poor service.
He said: 'We believe that all consumers of legal services - whether regulated or unregulated - should be able to access the ombudsman scheme. Service providers should be able to operate on a level playing field.'