Shares of electric car company Tesla have sunk more than 6 per cent after an internet video showed flames spewing from one of the company’s vehicles following a crash near Seattle.

Shares of Tesla Motors Inc fell $US12.05 ($A12.87) to $US180.95 ($A193.31) on Wednesday. It was the stock’s biggest one-day decline since July 16.

The automobile site Jalopnik.com posted the video that it says was taken by a reader. The video shows the front of the Tesla Model S in flames.

Tesla says the car hit a large metal object in the road on Tuesday, causing significant damage. The Californian company says the driver escaped unharmed and the blaze was put out by firefighters. The fire was limited to the front of the $US70,000 ($A74,780) car, Tesla said.

Trooper Chris Webb of the Washington State Patrol said the driver believed he had struck debris on the highway, triggering the fire, but a trooper who responded to the scene was unable to locate any objects on the roadway.

Tesla shares have risen more than 400 percent since the start of the year.