The driver of a semi-trailer that drove off the side of an elevated stretch of motorway and crashed has died after being trapped in the wreckage for 12 hours.

Authorities say the accident occurred at 11.30pm on Tuesday night on the Logan Motorway at Tanah Merah, south of Brisbane, but was not discovered until 10.30am yesterday (11.30am AEDT).

The truck was heading west on the motorway when it rolled down an embankment where the motorway passes over Slacks Creek, crashing into the ground below.

Police have now confirmed a 57-year-old man from New South Wales was pronounced deceased at the scene.

The clean up is expected to take hours but shouldn’t cause any further traffic delays on the Logan Motorway - which is now flowing freely @7NewsBrisbane pic.twitter.com/i1We9R5ewn — Mackenzie Ravn (@mackenzieravn) November 14, 2018

“At this point we’re unable to determine cause,” Acting Senior Sergeant Ben Reeve told journalists yesterday.

He added that the crash was first seen by someone walking. He said the truck would not have been visible to passing motorists.

“At this time it seems the truck has gone over the concrete barrier and then come to rest in the culvert,” he said.

“It would highly unlikely that motorists travelling at 100km/h to see that truck.”

Channel 9 helicopter vision from the scene on Wednesday afternoon showed the mangled wreckage and fire crews trying to access the cabin.

The destroyed Lindsay Transport semi-trailer was found surrounded by debris, having somehow come off the road.

Nearby residents told 9 News they heard a loud crash last night but could not see what had caused it.

It’s not yet know how the accident scene was discovered, given it was not visible except from above.

Queensland Police said eastbound lanes were closed with diversions in place at University Drive and Loganlea Rd.

Westbound lanes of the major motorway were down to one lane, with considerable delays in both directions.

Major delays on the Logan Motorway following a fatal truck crash near Meadowbrook. Police urging all drivers to avoid the area this afternoon and into tonight. @7NewsBrisbane pic.twitter.com/alaUEIoDCE — Mackenzie Ravn (@mackenzieravn) November 14, 2018

Traffic on Logan Motorway is at a standstill after a truck fell off the bridge. No further details have been released yet. pic.twitter.com/czm8vwlxu5 — Lucy Rees (@lucyrees96) November 14, 2018

Police are investigating the cause of the accident. No further details have been released.