The Law Society says the increasing number of people choosing to represent themselves in court is holding up the system, and costing time and money.
According to its research, 14 percent of High Court cases had unrepresented litigants last year, and the figure for the Court of Appeal was higher at 21 per cent.
Law Society president Chris Moore said more trials were being aborted as a result.
"When you have a trial aborted you've wasted the time of the judge, the jury, defence council, the prosecution council etc.
"And you're got to go through the whole process again, court staff and court time again."
He said more people were going to court without a lawyer because legal aid was harder to get and litigants are more aware of their legal rights thanks to the Internet.