Day five of the search for missing Gisborne preschooler Lucas Ward resumed this morning with police again checking the Waimata River near where his bike was found.

Four-year-old Lucas has not been seen since wandering off from his grandmother's home in suburban Kaiti about 3pm on Tuesday.

Divers were again scouring the river upstream and downstream of the grandmother's home in Graham Road this morning after police earlier said that they were "99 per cent sure" he was not in the water.

"I'm confident that our police divers have done a very, very good job of the area that they have searched and I'm confident that they feel he is not in there and they are 99 percent sure." said Gisborne police area commander Inspector Sam Aberahama this morning.

Mr Aberahama said police were not discounting the possibility of foul play, but there is nothing to indicate that.

"We are treating this incident as a missing person investigation. That type of investigation encompasses any potential aspects of foul play or a criminal element. It's an option we must consider."

Yesterday police took the hunt for Lucas into residents' bedrooms, searching wardrobes in homes near where the youngster disappeared.

There are no plans to scale down the search and investigators yesterday appealed for two kayakers, seen on the river around the time of his disappearance, to come forward.

Lucas' grandmother, Anne-Marie Hunt, found his bike, which he'd been playing on, at the top of a pathway leading to a jetty on her property.

She found a chip packet she had given him floating in the river.

Resident Edwina Ashwell said police had knocked at her door twice since Lucas disappeared. On Wednesday they searched inside.

"They even looked in the wardrobes, they asked if they could come in and we were happy to let them ... they looked around our backyard, over fences and into other people's backyards."

Ms Ashwell, who does not know the Ward family, set up a Facebook page providing updates on the search, urging people to check their backyards, and asking anyone with any information to call police.

"My sisters have been out looking all day but I can't because I have to work, so on my breaks I put up a Facebook page and people have been putting a lot of kind messages on it."

Gisborne police area commander Inspector Sam Aberhama confirmed to the Weekend Herald that police had searched some houses. "Some people spoken to have been asked if police can look inside ... there is no suspicion cast around anyone we would have done that to."

Tairawhiti Polytechnic student Karen Clune has been searching for Lucas every day.

Wearing a high-visibility vest with "Have you seen Lucas" written on the back, she walked along the Waimata River with her two dogs yesterday. "I'm thinking he might have broken his leg and is stuck somewhere."