A three-tonne steel coil fell onto a factory worker while he was replacing the rolls in a warehouse.

The worker was crushed by the huge steel rolls while on duty in the industrial parts factory in Samut Prakan, central Thailand on August 3.

CCTV footage shows the man controlling a pulley to move the steel coils when one one toppled over onto his legs.

Struggling to breath, he tried to push the heavy 3,000 kilogram metal off his body while shouting for help from his colleagues.

One of his co-workers who walked by the scene saw him suffering under the steel roll and rushed to help him while another worker helped removed the metal.

The emergency services took the worker to the hospital where he was found to be seriously injured with two broken legs.

Police said the incident was being dealt with internally by the factory and the injured worker.