Barristers leaving the profession say that difficulty in getting paid is one of their main reasons, the legal regulator has been told.
More than 335 barristers, or about 15pc of the Law Library, have asked legal accounts service LawServ to recover fees since October 2014.
But out of €4m in outstanding fees, just €1.1m has been recovered to date.
The figures were contained in a submission made by the Bar Council of Ireland to the Legal Services Regulatory Authority (LSRA) earlier this month.
The representative body for barristers said there were relatively high levels of attrition in some areas of law.
The submission detailed how out of 149 barristers who joined the Law Library in the 2010/11 legal year, just over half remained by September 2018.
Difficulty getting paid, cuts in legal aid and insufficient demand for services were the main reasons cited for high attrition levels.
According to the document, data provided by LawServ showed approximately 42pc of cases of non-payment of counsel fees arose from "a lack of cooperation" by the instructing solicitor to discharge the fees owed.
In a further 16pc of cases, the client did not have funds to pay fees.
In Ireland, barristers cannot act for a client in contentious litigation without being engaged by an instructing solicitor. Fees due to the barrister have to be paid to the solicitor first before being passed on to the barrister.
If a client does not pay, the solicitor has an obligation to take reasonable steps to seek to recover the fees for the barrister, but they are not strictly and personally liable for the barrister's fee.
In the submission, the Bar Council said it was hopeful the LSRA would investigate the issue and consider steps "to bring an end to the high rate of failure by solicitors to discharge fees properly due to counsel for work undertaken".
The LSRA began handling complaints against barristers and solicitors last October, a move which will phase out of the old system under which disciplinary matters were dealt with by the Law Society, the Solicitors Disciplinary Tribunal and the Barristers Professional Conduct Tribunal.
Law Society director general Ken Murphy told the Irish Independent that a failure by a solicitor to abide by their obligations to a barrister was considered "a very serious disciplinary matter".
But he added that where the Law Society had received complaints against solicitors over non-payment of barristers in the past, the overwhelming majority of cases were ones where the solicitor had not been paid either.
He said some clients simply didn't have the capacity to pay.
"The reality is there are bad debts in every business," he said.