South Korea's top technology university has been reported to have developed a plan to power electric cars through recharging strips embedded in roadways, using a technology to transfer energy found in some electric toothbrushes.

The plan, still in the experimental stage, calls for placing power strips about 20cm to 90cm wide and perhaps several hundred metres long into the top of roads, Reuters reported.

Vehicles with sensor-driven magnetic devices underneath could then 'suck up' energy as they travelled over the strips without coming into direct contact.

"If we place these strips on about 10% of roadways in a city, we could power electric vehicles," Cho Dong-ho, the manager of the 'online electric vehicle' plan at the Korea Advanced Institute of Science and Technology, told the news agency.

The university has built a prototype at its campus in Daejeon, about 140 km (90 miles) south of Seoul, for electric-powered golf carts and is working on designs that would power cars and buses.

The system, that can charge several vehicles at once, would allow electric cars and buses to cut down on their battery sizes or extend their ranges, Reuters said.

The non-contact transfer of electricity, also called inductive charging, works by magnets and cables on the underside of the vehicle making a connection with the current in the recharging strip to receive power as they travel over it.

It is employed in some brands of electric toothbrushes that are sealed and water resistant, and use a magnetic connection to receive energy while resting in a cradle connected to the mains supply.

The recharging strips, which are attached to small electrical stations, would be laid in places such as bus lanes and the roads running up to intersections so that vehicles could power up where traffic slows down, Cho said.

The system would be tested later this year for use in the bus systems of Seoul and other South Korea cities while some of the country's automakers are also cooperating in the project.

Unlike electric lines used for trams or trolley buses, vehicles do not need to be in constant contact with the strips and a person can touch the lines without receiving a shock, the news agency said.

The system so far has proven safe to humans and machinery, Cho told Reuters. The cost of installing the system is an estimated 400m won (US$318,000) per kilometre of road while the electricity cost is additional.