Deputy Premier and Police Minister Troy Grant heads a justice super agency, formed after the merger of the police ministry and attorney-general's department, in which the division previously sat.

Penny Musgrave, director of the  division for the past seven years, took redundancy on May 29.

University of NSW law professor David Brown said the division had an "honourable history" as a powerhouse of reform in the Wran government in public order, bail and sexual offences.

"Under subsequent governments of both persuasions it hosed down some of the more extreme, knee-jerk and ill-considered government legislation, often emanating from the premier's department," he said.

"Its closure will be a blow to sound, rational, evidence driven, criminal justice policy."

Ms Musgrave is understood to have resisted former premier Barry O'Farrell's proposal for nine mandatory prison sentences for alcohol-fuelled violence, which originally included four years prison for affray and two years prison for assaulting a police officer.

Only one mandatory sentence, an eight-year minimum for a one-punch assault causing death, passed Parliament.

In 2013, the NSW Bar Association complained to Mr O'Farrell that his government had taken the "unusual" step of bypassing the expert advice of the criminal law review division, and had instead asked former MPs Paul Whelan and Andrew Tink to "urgently review" police powers to arrest without warrant.

The chair of the NSW Law Reform Commission, another significant legal advice body, has meanwhile been vacant since January 2014.

Bail legislation recommended by the commission was dumped after one month last year, with the Baird government instead enlisting former MP John Hatzistergos to rush through new amendments.

"Trusted ex-politicians are being called on to produce instant reports, with minimal consultation ... It is a worrying and undemocratic trend towards consolidating executive power and removing expert professional scrutiny," said Professor Brown.

NSW shadow attorney-general Paul Lynch said the Baird government was taking a "cavalier attitude" to making sure its laws are right.

"The government has significantly downgraded its capacity to get the best advice it can on criminal law," he said.

Mr Lynch said some MPs had referred to the Criminal Law Review Division as "the thin blue line against the fascist police state".

A Department of Justice spokesman said the newly-named Justice Strategy and Policy Division had been given additional resources, and included a director of crime policy.

"Reviewing and advising on proposed legislation remains a vital function of the team," he said.

The Law Reform Commission was continuing to operate under a deputy chair, Peter Johnson, while recruitment was underway to fill the chairperson's position, the spokesman said.