Police and WorkCover are investigating

A man has been seriously injured when a pallet of scaffolding reportedly fell on him after he was hit by a forklift at a Barangaroo worksite in inner-city Sydney.

According to the ABC, emergency services were called to the construction site on Sussex Street on Saturday following reports of a workplace accident.

The man, believed to be aged in his 40s, suffered multiple injuries after he was struck by a forklift carrying pallets of scaffolding.

A pallet then fell off the vehicle and onto the worker.

Rita Mallia from the Construction Forestry Mining and Energy Union (CFMEU) says the man was injured in a "double whammy".

"There was a forklift driver that has not seen a worker that was working in an open area, [he] has hit that worker and one of the scaffold pallets has fallen off the forklift and hit the gentleman," she says.

"Apparently, he's in a very serious condition, but we're also very concerned about how this could occur and why it was that a forklift driver was not able to see a worker in his path.

"We're concerned that maybe the person who was driving the forklift truck was not a ticketed driver when in fact the ordinary driver was not here today."

The man was taken to Royal North Shore Hospital by ambulance in a serious condition with injuries to his legs and pelvis.

Police and WorkCover are investigating the incident.

In January last year, a man fell to his death at the Barangaroo construction site while working on scaffolding.