Rescue teams were called to Exeter Quay earlier after a report suggesting a woman was stranded in the River Exe.
Police in Exeter confirmed they recieved a call from a Quayside resident saying they had seen person floating in the Exe holding debris at 11.15 on Saturday morning.
The Police, Coastguard and volunteers from the Ashburton section of the Dartmoor Rescue Group established an incident command area and searched river banks in the afternoon and early evening.
The rescue team has been stood down.
Police have not released further details about the incident, but there is no indication anyone has been found.