NSW appealing release of triple murderer

The NSW government is appealing a decision by the state's parole board to release triple murderer and cop killer Berwyn Rees after almost 40 years behind bars.

The State Parole Authority in February confirmed its intention to grant parole to the now 69-year-old, who killed three men in the 1970s and 1980s including a serving police officer.

He will be subject to lifelong conditions when he is released, which could be as early as Thursday.

NSW Corrections Minister David Elliott on Tuesday said the government will seek a judicial review of the decision.

"I have instructed the Crown Solicitor's Office to commence judicial review proceedings in the Supreme Court of NSW," he said in a statement.

Rees was sentenced in 1981 to concurrent life sentences, with 27 years' non-parole, for the three murders.