The most high-profile detective in New South Wales has been taken off the investigation into missing boy William Tyrrell over alleged misconduct claims.

An internal investigation is under way into Detective Chief Inspector Gary Jubelin who last year led a fresh search for William, a NSW Police spokesman told AAP on Thursday.

It’s understood Det Insp Jubelin is being interviewed by the Professional Standards Command over his conduct on Strike Force Rosann which was set up to investigate the three-year-old’s disappearance.

He’s facing allegations relating to staff management and using a mobile phone without a warrant to record someone, AAP understands.

An inquest into William’s 2014 disappearance is due to be held in March and will run for a week before resuming in August.

“The acting state coroner and counsel assisting have been briefed, and the William Tyrrell inquest will proceed as planned,” police said.

William vanished while playing in his grandmother’s front yard at Kendall, on NSW’s mid-north coast, in September 2014.