Premier Mike Baird and Deputy Premier John Barilaro are working out details of the reshuffle, which is expected to be announced within weeks.

Mr Barilaro revealed last year that he had offered to keep Mr Grant in cabinet following his resignation as Nationals leader and deputy premier after a record swing against the party in the Orange byelection.

However, there is speculation Mr Grant will be stripped of some portfolio responsibilities, which cover justice, police, gaming and racing, and the arts, and that police might return to the Liberals.

Police Association president Scott Weber pointed out there had been eight police ministers in 10 years in NSW, when most other portfolios have had only five.

Mr Grant has held the Justice and Police portfolio since April 2015. Prior to that Stuart Ayres held the role of Minister for Police and Emergency Services for 10 months. He succeeded Mike Gallacher, who stepped down after an ICAC investigation.

Mr Weber said there was a need for stability as the force underwent a structural overhaul announced by Mr Baird, Mr Grant and Police Commissioner Andrew Scipione last August.

"Especially at this time, we need continuity and certainty while the process to modernise the [police force] is progressing," he said. "The government has the opportunity to deliver the necessary stability in this crucial portfolio by acknowledging, in any cabinet reshuffle, the need for the current minister to remain."

Mr Barilaro is believed to be pushing for a reallocation of Nationals portfolios following the loss of Orange, to better focus the party on its constituency.

One likely casualty is Education Minister Adrian Piccoli, who backed Mr Grant to remain in the Nationals leadership.

Health Minister Jillian Skinner is also under pressure to step aside in the interests of renewal, possibly into a more junior portfolio.