A Polish driver who was too sure of his GPS road navigation device ended up neck-deep in a lake after ignoring road signs warning of a dead-end ahead, Polish police said overnight.

"The man took a road that was closed a year ago when the area was flooded to make an artificial lake serving as a water reservoir - he ignored three road signs warning of a dead-end," police spokesman in Glubczyce, Piotr Smolen, said.

"It was still night time and he didn't notice the road led into the lake. His GPS told him to drive straight ahead and he did," Mr Smolen said, adding the driver had not been under the influence of alcohol.

The road ran straight downhill into the lake.

The Mercedes mini-van was nearly entirely submerged and was unable to back out on its own after being inundated with water.

The driver and two passengers escaped unharmed from the submerged vehicle and waited on its roof for police and fire rescue crews.

The driver placed the first call to emergency services while still inside the sinking van.

- AFP