Mr Scipione has revealed he will step down in April.

Premier Gladys Berejiklian and Police Minister Troy Grant joined him in making the announcement, revealing they would be a national hunt for his replacement.

The position would be advertised nationally, and an appointment made "following the merit-based assessment of candidates by an independent selection panel and Cabinet approval."

Ms Berejiklian and Mr Grant paid tribute to the outgoing commissioner.

"Our State has some of the lowest crime rates in the nation, and that is a credit to the hard work and dedication of Commissioner Scipione and the more than 16,000 police officers in NSW," Ms Berejiklian said.

"I thank Commissioner Scipione for his outstanding service to the people of NSW and I am certain that his legacy will live on in the NSW Police Force."

Minister for Police Troy Grant also thanked the Commissioner for his four decades as a member of the NSW Police Force.

"While today is not goodbye, it is a chance to reflect on just how crucial this role is in ensuring that we continue to have the best police force in the country," Mr Grant said.

Mr Scipione was due to retire from the position later this year but it is understood Mr Scipione will now bring forward his departure from the force.

The 58-year-old joined the NSW Police Force in 1980, became a deputy commissioner in 2002 before succeeding Ken Moroney as police commissioner in August 2007.

He will have been the longest serving police commissioner in NSW since Norman Allan held the post between 1962 and 1972.

Mr Scipione's contract as commission was extended by two years in 2015 after a police bugging scandal plagued the upper levels of the force and involved his two obvious successors - Nick Kaldas and Catherine Burn.

The two year extension was aimed at securing a smooth transition to appoint the next commissioner.

Since then Mr Kaldas has retired and the government has announced a restructure of the police hierarchy has increased the number of deputy commissioners from three to five.

Ms Burn and Dave Hudson remain as deputy commissioners but the government is yet to fill the other three vacant positions.

A spokesperson for the NSW Police Association said it was hoped the government would select "the most suitable applicant from the abundant pool of talent within the NSWPF."