South Africa has started testing a shark repellent electronic cable in Cape Town, in a high-tech experiment aimed at protecting swimmers without harming the deadly sea predators.

Researchers at KwaZulu-Natal Sharks Board installed a 100-metre-long cable on Friday in a small bay in Cape Town that seeks to exploit the sharks' super-sensitive nose.

The cable, fixed to the sea floor, has vertical 'risers' supporting electrodes, which emit a low-frequency, low-power electronic field that has been proven to repel sharks.

The technology has been developed by experts who invented a portable device called a "shark pod" that generates an electromagnetic field to protect scuba divers and surfers.

Research around the device shows that sharks turn away when they come across an electrical current. Sharks are sensitive around the eyes, gills and nose and some divers who routinely swim with them use small batons if they get too close.

'Fewer sharks ending up dead'

If successful, the technology could be used around the world and also mark a major shift away from the shark nets used on the South African coastline for the past 50 years, which have been criticized as environmentally unfriendly.

"Everybody is 100 per cent behind this project from the government to environmentalists, because this means we will have fewer sharks ending up dead from being trapped and tangled in the shark nets," said Paul Von Blerk, KwaZulu-Natal Sharks Board's technology specialist.

Everybody is 100 per cent behind this project from the government to environmentalists. - Paul Von Blerk, KwaZulu-Natal Sharks Board's technology specialist

The cable, which does not provide a physical barrier to sharks or other marine animals, will remain at the Glencairn beach for five months of testing.

Researchers chose the bay because sharks appear there frequently during the summer months. Clear waters in the area will also make it easier for monitors to see whether the barrier does prove a deterrent.

Researchers said the technology would not harm humans because the cable on the seabed would be covered, while the electrodes would only produce a tingling sensation if touched.

An Austrian tourist was attacked and killed by a shark while swimming at a beach in South Africa's Eastern Cape province in March this year, while the University of Florida says sharks killed 13 people off South Africa's coastline from 2004-13.