A construction worker at Sao Paulo's troubled World Cup stadium was killed after falling from a stand on Saturday, bringing the number of deaths at the venue to three.

The workman fell eight metres (26 feet) as he helped install temporary seating at the ground and was taken to hospital where his condition had been described as serious.

His employers said in a statement that he was observing all the necessary safety standards at the ground which will host the opening game of the World Cup between hosts Brazil and Croatia on June 12.

In November, two men died when a crane collapsed at the same ground.

The Sao Paulo stadium was one of six venues to miss an initial FIFA delivery deadline of December 31 and is only set to be handed over to organisers in mid-May.

A total of six workers have been killed during work on Brazil's World Cup venues.