This is the dramatic moment a driver and his passenger were rescued after their car plunged into the sea while boarding a ferry in Indonesia.

Footage shows a Daihatsu Xenia drifting in the water at the Merak Harbor in Banten province as those insider clambered to escape through a window on December 22.

Rescuers carrying life preservers paddled over to assist them as the vehicle slowly sank. Frantic locals also flocked to the docks to help pull the victims ashore.

Authorities citing witness reports said the car plummeted from the ship's ramp, which was not securely attached to the vessel.

Senior Commissioner Shinto Silitonga, Head of Public Relations for the Banten Police, said: 'Based on witness testimony, the position of the bridge at that time was not firmly attached to the ship. This caused the car to fall over.'

The victims, a couple named Yunianto Permono and Natasya Rosa, were taken to hospitals for treatment.

Shinto said investigations are ongoing to determine if the wharf manager has any liabilities in the case.

He said: 'We did not see any significant increase in sea waves and wind speed. In this context, there is no mention of natural causes.

'The investigation will prioritise the element of human negligence.'