Grave fears for eight-year-old missing in Western Australia's southeast

There are grave fears for an eight-year-old boy who has been missing for more than 33 hours in bushland in Western Australia.

The boy had been camping with his family at Fernhook Falls near Walpole when he was involved in a boating accident on Sunday morning.

It's believed he was kayaking in rapids when he disappeared. It is not known whether the boy could swim.

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More than 60 volunteers and police are now searching a 200-metre stretch of water. The search includes specialist divers in the deeper pools and an aerial drone.

Superintendent Kim Travers from the Great Southern District Police Force said heavy rain had hampered search efforts.

"The family are shocked. They are anxious and wanting us to find their boy," Superintendent Travers said.

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"The instinctive reaction to a child going missing is for a parent to throw themselves into searching for their child and that occurred."

Search efforts were called off on Monday evening, to be resumed at first light on Tuesday.