A woman has been rushed to hospital after a “terrifying” shark attack on the NSW south coast on Saturday morning.

The woman, believed to be in her 60s, was injured in an apparent attack off the main beach at Merimbula about 7am.

About 30 km of coastline has been closed for the next 24 hours as investigators search for the shark responsible.

Emergency services were called to the beach and paramedics treated the woman for bites to her shoulder, hip, back and buttocks.

She has been taken to South East Regional Hospital in a stable condition.

NSW Ambulance Inspector Robert Whitney said it was unclear at first how the woman was injured.

“There was initially some uncertainty if it was a shark, bystanders on scene reported seeing fins and a large animal,” he said.

“It was pretty clear that it had been a shark attack as paramedics arrived on scene.

“What we could see is that the patient suffered multiple wounds in what would have been a terrifying event. Paramedics did a fantastic job in treating the patient down at the beach before transporting to hospital.”

Surf Life Saving NSW said several beaches along the Sapphire Coast would be closed as investigations continued.

“Beaches from Wallagoot Lake down to Pambula are closed for 24 hours after a woman in her 60s was bitten on the hip and thigh by a shark while swimming at Main Beach Merimbula,” Surf Life Saving NSW said on Twitter.