New Zealand Sea Lion Trust volunteer Sian Mair said the visitor was a Weddell seal, a species of true seal more commonly found in the icy waters around Antarctica.
It was believed this individual was a juvenile male which hauled out at St Clair on Saturday night.
The about 1.5m Weddell seal appeared to be recovering from a minor injury to its shoulder, which could have been sustained through an interaction with a shark or a larger marine mammal, she said.
Unlike St Clair’s more common pinniped visitors, the New Zealand sea lion, Weddell seals do not have external ear flaps.
"It has a sort of rounded head and very soft features, so sort of nose slits opposed to a nose like our sea lion has.
"And then it also has basically non-existent fore flippers, so it would slide across the sand opposed to walking."
Ms Mair was at the beach yesterday to ensure everyone was being respectful, and that dogs were kept on leashes while they walked past the animal.
"And honestly, everyone’s been wonderful", she said.
The Department of Conservation’s classification series lists the species as a non-resident native animal, a "vagrant" which meant fewer than 15 individuals were expected to visit New Zealand each year.
Ms Mair said the last time a Weddell seal visited Dunedin was four years ago.