Hato Hone St John was notified of an incident at Brighton Beach about 1.30pm and responded with one ambulance and one first response unit.
Their crews assessed and treated one patient who was transported to Dunedin Hospital in a moderate condition.
Fire and Emergency (Fenz) were also on standby at the scene.
The incident involved a sea lion biting the leg of the unsuspecting surfer.
The surfer appeared in good spirits after he was helped to the ambulance.
Department of Conservation operations manager Gabe Davies said it was fairly common for people to see seals or sea lions in coastal environments.
"On the land, we ask people to stay at least 20m away from them," Mr Davies said.
"In the sea, seals and sea lions are more curious and will sometimes investigate people.
"It's extremely uncommon for these interactions to be other than gentle. "
