Two teenagers who'd parked their car at a picturesque lookout on the NSW mid-north coast are lucky to be alive after their 4WD plunged off a cliff and fell 20 metres onto rocks below.

The 17-year-old boy and 16-year-old girl inside the car miraculously escaped injury after the car drove over the Forster cliff and was only stopped from falling into the ocean by a large boulde.

The P-plater behind the wheel had gone to drive away from the Second Head Lookout car park on Monday night when he crashed through the barrier instead.

The teenagers later told police the driver had accidentally put the car into drive instead of reverse, a NSW Police spokeswoman said on Tuesday.

17 yo male driver and 16 yo female passenger lucky to escape with minor injuries after crashing down 20m cliff @PRIME7NthCoast @7NewsSydney pic.twitter.com/SR4ooCR4hM — Kristy Coulcher (@KCoulcher) September 25, 2017

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The teenage driver said he meant to put the car into reverse. Source: 7 News

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Unfortunately he put it into drive. Source: 7 News

Remarkably, the teens only suffered minor cuts, bruises, and possible concussions.

While the pair were able to climb out of the wreckage unassisted they were lucky a number of witnesses in the car park were quick to call emergency services who climbed down the cliff to rescue them.

The car, which belonged to the boy's father, was a complete writeoff but fortunately was insured.

A crane was called out to the scene on Tuesday afternoon before wining the Toyota out just after 1pm.