The bill is said to rely on "too many guesstimates"

A Justice 2 Committee report, ahead of a proposed Legal Profession Bill, will be published on Friday.

The Law Society said plans for a Scottish Legal Complaints Commission contained gaps which needed clarifying.

MSPs have also queried how difficult the separation of the complaints procedure will be to implement.

The Legal Profession and Legal Aid (Scotland) Bill would create an independent body to handle complaints against lawyers.

The bill relies on too many guesstimates Douglas Mill Law Society of Scotland chief executive

The majority of complaints commission members would be non-lawyers, but while it would handle issues about the service provided by lawyers, fees and conduct would still be dealt with by the Law Society of Scotland and the Faculty of Advocates.

The bill as a whole has been backed by committee members but some have called on ministers to explain how separating the complaints procedure will work in practice and how funding will work.

Douglas Mill, chief executive of the Law Society of Scotland, has raised similar concerns.

Greater compensation

He said: "The committee have had a difficult task to do in examining proposed legislation in which there are many gaps, and about which there remain many unanswered questions. The bill relies on too many guesstimates.

"Regulation of solicitors is a complicated process and to ensure there is real improvement for consumers, the public and solicitors, we need a fuller picture from the Scottish Executive sooner rather than later."

Leading figures have also raised concerns over whether some aspects of the bill are compatible with human rights law.

Under the legislation, the maximum amount of compensation people would be able to receive for inadequate personal service complaints will be raised from �5,000 to �20,000.

The bill also seeks to improve the delivery of publicly-funded legal advice.