Department of Conservation staff are shocked at the shootings of a sea lion and leopard seal on a stretch of Southland coastline.

Biodiversity programme manager Jessyca Bernard the sea lion was found at Waipapa Point and the leopard seal was discovered at nearby Waikawa Harbour.

She says they were gunned down and left to rot on the beach in a senseless act.

The New Zealand Sea Lion is fully protected under the Marine Mammal Act and is one of the rarest sea lion species in the world.

DOC is appealing for anyone with information to speak up.

The offender could face a fine of up to $250,000 or six months in prison.