A search for a toddler missing on the NSW mid-north coast will be scaled back after a desperate six-day operation has failed to find any trace of the three-year-old.
William Tyrell was last seen at his grandmother's house in Kendall, near Port Macquarie, last Friday.
Scores of police and volunteers have searched the regional town, including bushland and waterways, over the past six days.
Sniffer dogs have also been involved but have not picked up any trace of William.
The search will be scaled back on Wednesday night but a large team of investigators will continue to work on the case.
Superintendent Paul Fehon says the boy could not be alive after so long, if he was in bushland.
"The experts cannot substantiate that survival in the bush would be there at this point time," Fehon told reporters.
But Supt Fehon said police are still open-minded about what has become of young William.
"We have no indication of whether young William is out in the bush or whether other forms of human intervention are involved," he said.
A police strike force has been set up to investigate the disappearance.
Specialist police, including officers from the sex crimes squad have been brought in.
Known sex offenders in the area have been contacted to confirm their whereabouts at 10.30am last Friday.
"There has been nothing confirmed other than young William was playing in (the) yard with (his) sister that day," Supt Fehon said.
A friend of the Tyrell family, Nicole, said William loved being outside but knew the limits.
