Police say they have "major concerns" after a 2m inflatable raft was found on the Hutt River.

The yellow raft was found floating past the Tait rocks about 11.15am.

It was first spotted in the river, partly submerged at about 10am floating between Ferguson drive and moonshine road.

Police said in a statement: "Police have major concerns for any people that may have been in the water at the time with the raft and are seeking information from anyone who has any knowledge about the raft."