Hundreds of defence solicitors are poised to take strike action over plans to make some suspects pay a financial contribution to their legal aid, which would be collected by solicitors.
Critics have warned it will turn lawyers into debt collectors and risk leaving those accused of crimes without representation if solicitors concerned about their ability to pay turn their cases down.
Members of the Edinburgh Bar Association and Glasgow Bar Association have already voted in favour of industrial action over the issue if the legislation to introduce the changes is passed next week.
A demonstration is planned to take place outside the Scottish Parliament on Tuesday, when the proposals will be debated.
Mark Harrower, vice-president of the Edinburgh Bar Association, claimed the impact of the changes could result in huge problems for the court system.
"There is going to be an increase in adjournments, where lawyers make sure they are going to get paid for the case before they actually do it," he said. "There will be more cost to the public purse as adjournments cost money."
The plans would see those accused of crime in summary, or non-jury, criminal cases who have a disposable income of £68 a week or more – or £750 in savings – being asked to make a financial contribution to their legal costs.
Harrower said defence solicitors would be reluctant to take on cases if they were not sure if the client would pay their contribution, which could be as much as £485.
The Scottish Government has said the reforms would save nearly £4 million a year and that 80% of applicants for criminal legal aid would be unaffected by the changes.
A spokeswoman said: "We cannot maintain the current legal aid scheme without making the savings in the Bill."