AN elderly Brisbane man heading to Cape York on a fishing trip is in a serious condition after his car plummeted 18m off a remote bridge.

The 75-year-old's four-wheel drive plunged off the Little Laura River bridge which is about 15km north of Laura and he was trapped inside the vehicle for more than two hours while waiting for emergency services to reach the site.

He was flown by Rescue 510 helicopter to Cairns Hospital with serious head, neck, chest and leg injuries.

It was the second serious crash involving tourists in Cape York this week after a Brisbane man died following a head on collision near Bamaga on Sunday.

Laura police Sen-Constable Adam Frew said the man had driven off the bridge in an effort to avoid a head-on collision with another motorist travelling in the opposite direction.

He said the driver had been conscious and talking at the scene, while his male passenger escaped virtually unscathed.

There were three men in the other southbound car and none were injured.

Volunteers from the Lakeland State Emergency Services and Cooktown auxiliary firefighters, along with an off-duty firefighter who had been in the area at the time, led efforts to free the man from his car.

Queensland Fire and Emergency Services Cooktown Captain Jason Carroll said they had to cut the roof off the vehicle to get the man out, then they used a human chain to carry him on a stretcher to the rescue helicopter.

"Everyone worked so well together," he said.