Tesla Motors' Model S sedans that were built after September 2014 feature an 'autopilot' system, CEO Elon Musk has said.

However, Musk added that the functionality was in beta mode and drivers should not completely remove their hands from the steering wheel while driving, Reuters reported.

"We're being especially cautious at this stage so we're advising drivers to keep their hands on the wheel just in case. Over time there will not be a need to have your hands on the wheel," Musk said.

If drivers took their hands off the steering wheel while driving, an alert saying "hold steering wheel" illuminates on the dashboard. In difficult navigating conditions, an audio alert is heard, and after that also if the driver does not put his hands back on the wheel the car will slow down and then stop.