The Search for missing Western Australian girl Cleo Smith has now entered its fifth day, with authorities desperately pleading for anybody with information, big or small, to come forward.

Interstate Police have now joined the public appeal as the hunt goes national, but as the days continue to pass without turning up any trace of the child, hopes have begun to fade.

Cleo was last seen at 1.30am on Saturday in a tent she was sleeping in with her mother Ellie Smith and stepfather Jake Gliddon at the Blowholes campsite in Macleod, north of Carnarvon.

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Cleo's parents say when they woke just after 6am, Cleo, along with her sleeping bag were nowhere to be seen.

Despite exhaustive search efforts across land, air and sea, no evidence leading to the four-year-old has been found.

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WA Police Inspector John Munday said by this time in the investigation, the little girl "could be anywhere".

"The reality is if we do explore the scenario that there is third party involvement and Cleo has been taken from this area by somebody, we are in day four, they could be anywhere," he said.

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Yesterday, weather conditions forced the search to a halt for more than six hours as the Gascoyne region was battered by storms.

Police earlier called off the marine and sea-based search and instead turned efforts to focus on nearby coastal shacks.

Mounted section officers, helicopters, along with police and even ADF drones have all been deployed to help locate Cleo.

But police are determined for a positive outcome, saying that they are "throwing everything" at the effort.

"We will continue until we can provide some answers into what has happened to Cleo," Mr Munday said.

Anyone with information is asked to call police immediately on 131 444. Callers are asked to provide the reference number CAD 781784.