An unoccupied boat washing ashore off a suburban beach near Hobart has triggered an air and sea search.

Tasmania Police said the white flybridge cruiser with a small inflatable dingy attached washed onto Kingston Beach about 2.05pm on Wednesday.

On Wednesday afternoon, Tasmania Police said rescue teams had taken to the water in boats and the Westpac Rescue Helicopter had joined the search effort, with another helicopter also flying in patterns up and down the River Derwent.

Police said they had been "making enquiries in relation to the owner of the vessel".

Anyone who has any information is asked to contact police on 131 444.