Divers have again been searching the area where a kayaker went missing in Tasmania's south east.

27-year-old South Australian William McCallum was last seen on Sunday in a sea kayak at Dover, south of Hobart.

Acting Inspector Marcus Pearce says there is no real chance he's still alive, and they're now looking for a body.

Mr McCallum was last seen in the Port Esperance area and his upturned kayak, a paddle and a pair of gumboots were found on Sunday night.

Members of William McCallum's Adelaide family joined yesterday's search, which involved three police boats, eight SES volunteers and a helicopter.