Detective Chief Inspector Gary Jubelin, who commanded dozens of officers on Strikeforce Roseann for four years, was taken off the Tyrrell case in March while he was investigated over allegations of misconduct.

Mr Jubelin had investigated other major crimes, including the murder of Mathew Leveson and the Bowraville case in his 34-year career.

A report from the internal misconduct investigation is yet to be made public.

Police Minister David Elliott said he had no concerns about the William Tyrrell investigation.

"I have the absolute confidence of the NSW Police Force to do a thorough investigation into any matter," he told reporters on Sunday.

NSW Premier Gladys Berejiklian thanked Mr Jubelin for his contribution.

An inquest into the disappearance of William will continue in August.

In one of the state's biggest mysteries, the three-year-old disappeared from foster grandmother's home at Kendall on the mid north coast on September 11 in 2014.

The inquest has been told the police investigation into William's disappearance was ongoing, with many officers still working hard to solve the mystery.

Australian Associated Press