Police search scrub for missing NSW boy

William Tyrell hasn't been seen since Friday but authorities and members of the mid-north NSW community from where he went missing aren't giving up their search for the three-year-old.

On Monday extra volunteers and police arrived to bolster the search, which is concentrating on a 1.5 kilometre radius around William's grandmother's Kendall home.

William was last seen at the home in a Spider-Man costume on Friday morning.

"The window of opportunity for survival is still there, so while ever that is there we will continue with our search," Superintendent Paul Fehon said.

Mounted police, dog teams, SES, members of the Rural Fire Service, local surf lifesaving club and hundreds of volunteers have spent the weekend searching for the boy, but they're yet to find anything that could lead them to William.

Police divers have also scoured nearby dams.

On Monday afternoon police released more photos of William hoping it would prompt someone with information to come forward.

Supt Fehon earlier said investigators were "keeping an open mind" about whether the boy had been taken.

But when pressed further he said police wouldn't "go into operational matters but we look at everything."

The full-scale search will continue Tuesday.