The body of a fisherman has been found after the man was swept away in the Chilliwack River, east of Vancouver, when his waders filled with water.

Chilliwack RCMP say the man's body was located about four hours after the Wednesday afternoon incident.

The unidentified victim had been swept under a log in Chilliwack Lake near the mouth of the river, about 125 kilometres east of Vancouver.

Witnesses tried to help the fisherman as he floated down the Fraser Valley-area river but because his hip waders were full of water he was too heavy to pull to safety.

He slipped from the grip of rescuers and was not seen again.

Police are urging the public to exercise caution around the Chilliwack River, saying it is extremely fast-moving and very cold.