According to workers, a 50-tonne steel rafter slipped for about three feet down, creating a huge bang but causing no injuries.

Australian construction company Multiplex said in an official statement that the incident didn't affect the structure of the stadium.

"At this point we believe that this is a minor incident," said Multiplex chairman Martin Tidd.

"However as Multiplex has rigorous health and safety guidelines, we have taken the cautious measure of evacuating the site of the 3,000 plus workers until we have a full report on the incident."

This wasn't the first incident in the construction site as a man was killed in 2004 after a collapse of scaffolding.