The victim has been airlifted to hospital following the incident.

CAPE TOWN - The victim of a shark attack at Muizenberg beach on Friday afternoon has been airlifted to hospital and is in a stable condition.

National Sea Rescue Institute's Craig Lambinon says "The emergency services were activated to Muizenberg beach just in front of the pavilion where a 20-year-old man from Newlands, originally from Durban, was bitten on the legs by a shark."

The victim had multiple lacerations to his lower limbs, some of which were deep lacerations, and an avulsion to the left thigh.

A member of the public began first aid treatment on the scene prior to the arrival of paramedics.

At the time of the incident shark spotters were flying the black flag and a bystander approached them to say they had seen a fin in the water.

The incident took place when the shark siren was in the process of being activated.

Based on eyewitness accounts, it's believes a great white shark bit the man.

Shark Spotters and law enforcement officers have closed Muizenberg Beach.

Expert Gregg Oelofse says he spoke to the victim on the scene.

"I used his cellphone to phone his dad who is in Durban and got him to speak to him. He told his dad not to worry, he is going to be okay.

"His dad was chuffed to hear from him obviously. To all of us, we were concerned. He had some very bad lacerations to his leg. The paramedics were very confident he would make a full recovery."