Responding to reports of a person asking Kendall businesses about the whereabouts of Benaroo Drive on Friday, Superintendent Paul Fehon said investigators were continuing to examine all leads.

"We need to go through that information, collate it, analyse it and we need to substantiate or discount that information that's provided to us," Superintendent Fehon said.

Investigators remain open-minded to William's whereabouts as there is "no indication whether young William is out in the bush or whether other forms of human intervention have been involved," Superintendent Fehon said.

Police have asked anyone who knows a person or car that was using Benaroo Drive or in Kendall on Friday to contact Crime Stoppers on 1800 333 000.

EARLIER: Police have said there is little chance missing three-year-old William Tyrell is still alive, if the little boy is lost in dense bush near Kendall. 

Superintendent Paul Fehon made the announcement at Kendall Showground on Wednesday morning when he referred to expert advice on the sixth day of the search.

"They cannot substantiate his survival, at this point in time," Superintendent Fehon said when asked about William's likely condition if he is lost.

Supt Fehon repeated police's request for information on any vehicle which may have been in the Kendall area on Friday morning, because "we still have no indication of where he is."

Superintendent Fehon also said police are investigating whether "human intervention" was involved in William's disappearance.

"Human intervention can include a number of things," he said when asked for clarification,

While volunteer numbers have fallen since Monday, and are likely to continue to decrease as time goes on, Superintendent Fehon said police will continue to dedicate resources to the operation.

In addition to officers from the Mid North Coast and Manning-Great Lakes Local Area Commands, the Public Order Squad will again comb the three kilometre area around where William was last seen on Friday morning.

Strike Force Rosann has been created to investigate the incident and includes members of the State Crime Command, under its Serious Crime Directorate, who investigate sex crimes as well as disappearance cases. Detectives from the Mid-North Coast and Manning-Great Lakes Local Area Command also are included. 

Trail bikes and four-wheel drive vehicles will be used to expand the search area on Wednesday.  

Crime Stoppers can be contacted on 1800 333 000.