This is the moment a toddler was knocked over by a large piece of timber when clumsy labourers dropped the item.

The men were repairing a roof over a driveway in the city of Chenzhou in Hunan, China, when the accident happened on April 9.

As they raised the roof structure, a wooden beam that was supporting it was suddenly freed and toppled over, hitting the little child on the head.

The boy was instantly knocked unconscious as his mother grabbed him and then, apparently fearing further collapses, picked him up and took him out from under the structure.

But the workmen and the men she was talking to stared in surprise at what happened and did nothing to assist the woman as she cared for the boy who ended up with a badly bruised head.

Fortunately, the child suffered no other injuries as a result of the mishap.