A directions hearing was held at Glebe Coroners Court on Wednesday ahead of an inquest into the three-year-old's suspected death.

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

The Sydney inquest will begin before deputy state coroner Harriet Grahame in March and run for a week before resuming in August.

Counsel assisting the coroner, Gerard Craddock SC, told Wednesday's hearing it wasn't possible - at present - to conclude William was dead.

"The police investigation into his disappearance is ongoing and police are following active leads at present," Mr Craddock said.

He said William was in foster care and that, combined with the circumstances of his disappearance, meant there was jurisdiction to hold an inquest.

The coroner ordered that the Department of Family and Community Services provide a statement including the history of its dealings with William's parents, his removal from their care and his placement in out-of-home care.

William's foster carers, who attended the hearing, made no comment as they left the court.

Earlier this year, a targeted search of bushland near William's grandmother's home in Kendall found no signs of him but detectives did get information relevant to the investigation.

The search in June and July was designed to rule out William dying in a case of misadventure.

Australian Associated Press