NSW Bar Association president Arthur Moses, SC, has written to the Berejiklian government and the Labor opposition urging them to amend existing laws to raise the retirement age.

The association is also pushing for a related, and likely more controversial, change that would lift the age at which judges qualify for a generous pension after at least 10 years' service from 60 to 65.

Mr Moses said there were "compelling reasons" to lift the judicial retirement age to 75, including stemming the loss of experienced judges "who would otherwise have had the capacity to continue to make significant contributions to the development of the law".

He said the pension change - which would apply to judges retiring voluntarily before the new retirement age of 75 - "would represent a significant cost saving for the public" and encourage judges to remain in office rather than retiring early and embarking on another career.

Mr Moses said the savings should be used to increase the legal aid rates paid to junior barristers, which have remained static since 2007.

Attorney-General Mark Speakman said the association's proposals were "interesting and I will certainly consider them".

The shadow attorney-general, Paul Lynch, said he was "supportive in principle" of the plan.

"I've thought for some time that what the profession calls the 'age of statutory senility' was set too low," Mr Lynch said.

"It doesn't take account of changing demographics."

Retirement ages for judges and magistrates differ between the states and territories, ranging from 65 to 72.

Generally, those who have reached the retirement age can be reappointed as acting judges for a limited time on an ad hoc basis. In NSW, the age cut-off for acting judges is 77.

Judges of the High Court and Federal Court must retire at the age of 70 and cannot return as acting judges.

Mr Moses said lifting the age at which judges would qualify for the full pension after 10 years' service would only apply to judges appointed with the new retirement age.

Judges who have served for 10 years and retire voluntarily on or after the age of 60 are currently entitled to an annual pension of 60 per cent of their full salary. Supreme Court judges are paid $441,940 a year.

A lower pension - 25 per cent of the full salary plus 5 per cent for each year, or part of each year, served over five years - applies to those who have served on the bench for less than 10 years.

Mr Moses said the budget savings should be used to "fund other areas which have been ignored in the justice portfolio" and the association had "serious concerns" about barristers devoting "long hours of unpaid work to legal aid cases".

"If an agreement cannot be reached, we will be seeking the appointment of an arbitrator to review legal aid rates paid to the private bar which will involve a work value study," Mr Moses said.

Mr Speakman said he understood "the bar association's concern about remuneration for junior barristers, although the NSW government will not be engaging in any arbitration process in this regard".

Mr Lynch said "whatever savings might be achieved should be used in the underfunded legal system, not delivered back to a rapacious Treasury".

"Certainly the most underfunded component of the system is the legal assistance sector, from legal aid rates for junior counsel and solicitors to funding for community legal centres," Mr Lynch said.