The Department of Conservation was investigating the incident on Middle Beach yesterday, which left a Weddell seal with multiple puncture wounds.
Doc Otago ranger Jim Fyfe said details were still unclear, but the seal had some bloody marks on its body and around its neck and head.
"These animals are pretty robust and they recover pretty quickly from injuries.
"They would need to in the ocean, so we’re not concerned that the injuries are by any means fatal."
It was rare for a Weddell seal to be seen on Dunedin beaches, as they were usually found around the Antarctic.
"It’s pretty special that it’s arrived and spending time on the beach here. We’re not sure why."
Mr Fyfe said the owner of the dog had contacted Doc to report the incident.
"It’s certainly disappointing that these rare species that do visit are harassed and attacked in this sort of way by our four-legged friends," Mr Fyfe said.
It was up to dog owners to check beaches before letting dogs off their leash, he said.
If they did see any wildlife, there was a bylaw that stated they had to keep dogs on their leash within 20m of it.
