A truck crash on the South Eastern Freeway in Adelaide caused major traffic delays this morning.

SA Police said a truck crashed into a concrete barrier near the Stirling on-ramp just before 2:20am.

The driver was not injured, but the freeway was closed for outbound traffic for several hours.

Police said the truck and two trailers were towed from the scene just before 7am.

Traffic in both directions was affected and heavy vehicles were stopped at the bottom of the freeway and held up for several hours.

Matthew Bowman from the Department of Infrastructure and Transport said the incident had caused "significant disruptions to traffic".