'We need to find him today': Search for missing NSW toddler William Tyrell expands

Police are expanding the search for a three-year-old boy who was last seen wearing his Spiderman suit on NSW's mid-north coast.

William Tyrell went missing about 10.30am on Friday from the front yard of a relative's home at Kendall.

Authorities, including police and members of the SES, Rural Fire Service, the surf lifesaving club and more than 100 local volunteers have been combing nearby bushland since his disappearance.

Last night police divers also began searching surrounding dams.

“He has had no food, no water, and is likely to be in a poor state of health,” Inspector Kim Fehon told a press conference this morning.

“We need to find him today,” she said.

Mounted police, Polair, the dog squad and officers on trail bikes are all involved.

He is described as being of Caucasian appearance, with dark hair and hazel eyes.