The Law Society Of Scotland has warned the Courts Reform (Scotland) Bill, which proposes moving the bulk of personal injury cases from the Court Of Session in Edinburgh to sheriff courts, could adversely affect access to justice.
The professional body for solicitors says that although more cases will be heard in the courts, there will be little increase in the number of sheriffs, leading to delays in their determinations.
The Faculty Of Advocates has said legal representation will be pushed out of the reach of ordinary people.
The move, it says, will favour people with "deep pockets" and see litigants in Scotland labouring under disadvantages not faced by people elsewhere in the UK.
Solicitors have already warned against the abolition of the centuries-old legal requirement for corroboration, where two individual pieces of evidence are needed to bring a prosecution.
Justice Secretary Kenny MacAskill has said the court reforms will lead to the largest overhaul of the system in a generation, bringing more efficiency with reduced costs and delays.
It would see only the largest civil cases heard in the Court Of Session, Scotland's leading civil court, and a new court created to deal with civil appeals and less serious criminal appeals.
A key proposal in the consultation is raising the threshold under which the sheriff court can deal with civil cases from £5000 to £150,000 - five times the equivalent figure in Northern Ireland and three times that in England and Wales.
Litigants would have the choice of proceeding only in the sheriff court, or in the Edinburgh court if the claim was above the new higher threshold.
The Scottish Government says the move will free up the Edinburgh court to deal with the biggest cases. The Faculty is concerned it will deny many people the right to instruct counsel at the Court Of Session.
It says in a sheriff court use of counsel has to be sanctioned, a practice that is not the norm in courts elsewhere in the UK.
Fiona Robb, secretary to the Law Society Of Scotland's civil justice committee, said: "We think the Scottish Government is right to raise the threshold; however, we would prefer to see the limit set at no more than £50,000.
"The Scottish Courts Service needs to ensure sheriff courts are properly resourced to manage this significant transfer of business, particularly with the programme of closures taking place across the court estate. We think there should be training for specialist sheriffs and IT systems need to be improved.
"Without sufficient resources, court users and the administration of justice overall could face substantial delays."
The bill also proposes to introduce a three-month time limit on judicial review cases. The society says this measure will restrict access to justice.
The faculty said the £150,000 proposal would deprive litigants of choice.
In practical terms, the faculty said, it would "undermine the right of litigants to instruct counsel, favouring litigants who can afford to instruct counsel irrespective of the recoverability of counsel's fees.
It added: "If clients are to receive justice, they need to be represented by advocates who are trained and skilled in analysing the issue, in marshalling and presenting the evidence, and in advancing legal submissions."
A Scottish Government spokeswoman said the bill would ensure the "right cases are heard in the right courts - reducing delays, cost and bureaucracy, and improve access to justice for all.
"Lord Gill's Civil Courts Review [which preceded the bill] identified that litigants are paying disproportionately high costs where they litigate in our highest court. Raising the sheriff court privative limit aims to ensure more proportionate costs for parties in civil actions."
She said a new specialist personal injury court would take many of the cases from the Court Of Session, adding: "The sheriff courts are well placed to handle the transfer of business because the total cases coming out of the Court Of Session is only about 3% of the civil caseload in the sheriff courts."