With just two days to go until the 2014 World Cup opener in Sao Paulo, an accident at a construction project to build a monorail in Brazil’s largest city has killed a worker.

The incident occurred near Brazil’s busiest domestic airport, and comes as public sector strikes, mass unrest and crippling delays threatened to overshadow the start of the biggest event in world football this Thursday.

The monorail project is itself an example of a massive infrastructure which the Brazilian government said would be a positive legacy from hosting the World Cup.

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But in 2011, just a year after construction began, officials had already declared that it would not be ready in time.

Authorities said one man was killed and another injured yesterday when a large concrete support beam fell from an under-construction section of the 17.7km monorail track.

Shape Created with Sketch. In pictures: Brazil unrest ahead of World Cup 2014 Show all 20 left Created with Sketch. right Created with Sketch. Shape Created with Sketch. In pictures: Brazil unrest ahead of World Cup 2014 1/20 Brazil Brazilian protesters take over the Cristo Redentor statue viewing platform in Corcovado, Rio de Janeiro. The protestors ask for improved funding for public education instead of expenditures in athletic events 2/20 Brazil Demonstrators run from tear gas fired by police outside Ana Rosa subway station during the fifth day of metro workers' strike in Sao Paulo 3/20 Brazil Riot police forces stand guard during a demonstration by striking subway workers and members of the MTST (Homeless Workers' Movement) in Sao Paulo 4/20 Brazil Metro's workers demand 12.2 percent salary raise. The five-day-old strike has already caused massive traffic jams in Brazil's largest city as its new stadium prepares to welcome more than 60,000 fans for Brazil-Croatia game 5/20 Brazil Striking subway workers and members of the MTST (Homeless Workers' Movement), demonstrate at the Cathedral of Sao Paulo 6/20 Brazil Striking subway workers and members of the MTST (Homeless Workers' Movement) walk through the streets of Sao Paulo 7/20 Brazil A court set a 500,000 reals penalty ($223,000) for each day metro workers' union members stay off work from Monday and also declared the strike illegal, complicating preparations for the World Cup opening match 8/20 Brazil Striking subway workers and members of the MTST (Homeless Workers' Movement), are dispersed with tear gas by police forces as they demonstrate in Sao Paulo 9/20 Brazil Striking subway workers and members of the MTST (Homeless Workers' Movement), demonstrate in Sao Paulo 10/20 Brazil "The World Cup here in Brazil is the worst thing in the world for workers. They are investing in stadiums and forgetting the people" said Umberto Rocha, a director of a union for Rio security guards 11/20 Brazil Policemen in riot gear walk inside Ana Rosa subway station during the fifth day of metro worker's protest in Sao Paulo 12/20 Brazil Activists stage a protest in front of the municipal stadium in the town of Sorocaba prior to a training session by Japan's national soccer team 13/20 Brazil Activist Sara Winter poses for the picture during her anti World Cup protest in Rio de Janeiro's Ipanema beach. Written on her body in English is the phrase, "While your team is relaxing, Brazilians are dying" 14/20 Brazil Guarani Indians occupy the "Bandeirantes" monument during a protest in Sao Paulo 15/20 Brazil A rafter is seen on the ground at a construction site for the monorail where one construction worker died and two workers were left injured after one of the rafters collapsed in Sao Paulo 16/20 Brazil The rafter in Sao Paulo collapsed due to unknown reasons 17/20 Brazil Subway train operators, along with activists from social movements, clash with riot police in front of the Ana Rosa metro station, in an ongoing subway strike, in Sao Paulo 18/20 Brazil Authorities are deeply worried about the strike because the subway is the main means of transportation for World Cup fans scheduled to attend opening match when Brazil takes on Croatia 19/20 Brazil A police officer pepper sprays strikers and protesters during a clash with riot police in front of the Ana Rosa metro station, in an ongoing subway strike by operators in Sao Paulo 20/20 Brazil Brazilian are furious over Christ the Redeemer statue in Rio de Janeiro dressed in a giant Italian football shirt for a television commercial 1/20 Brazil Brazilian protesters take over the Cristo Redentor statue viewing platform in Corcovado, Rio de Janeiro. The protestors ask for improved funding for public education instead of expenditures in athletic events 2/20 Brazil Demonstrators run from tear gas fired by police outside Ana Rosa subway station during the fifth day of metro workers' strike in Sao Paulo 3/20 Brazil Riot police forces stand guard during a demonstration by striking subway workers and members of the MTST (Homeless Workers' Movement) in Sao Paulo 4/20 Brazil Metro's workers demand 12.2 percent salary raise. The five-day-old strike has already caused massive traffic jams in Brazil's largest city as its new stadium prepares to welcome more than 60,000 fans for Brazil-Croatia game 5/20 Brazil Striking subway workers and members of the MTST (Homeless Workers' Movement), demonstrate at the Cathedral of Sao Paulo 6/20 Brazil Striking subway workers and members of the MTST (Homeless Workers' Movement) walk through the streets of Sao Paulo 7/20 Brazil A court set a 500,000 reals penalty ($223,000) for each day metro workers' union members stay off work from Monday and also declared the strike illegal, complicating preparations for the World Cup opening match 8/20 Brazil Striking subway workers and members of the MTST (Homeless Workers' Movement), are dispersed with tear gas by police forces as they demonstrate in Sao Paulo 9/20 Brazil Striking subway workers and members of the MTST (Homeless Workers' Movement), demonstrate in Sao Paulo 10/20 Brazil "The World Cup here in Brazil is the worst thing in the world for workers. They are investing in stadiums and forgetting the people" said Umberto Rocha, a director of a union for Rio security guards 11/20 Brazil Policemen in riot gear walk inside Ana Rosa subway station during the fifth day of metro worker's protest in Sao Paulo 12/20 Brazil Activists stage a protest in front of the municipal stadium in the town of Sorocaba prior to a training session by Japan's national soccer team 13/20 Brazil Activist Sara Winter poses for the picture during her anti World Cup protest in Rio de Janeiro's Ipanema beach. Written on her body in English is the phrase, "While your team is relaxing, Brazilians are dying" 14/20 Brazil Guarani Indians occupy the "Bandeirantes" monument during a protest in Sao Paulo 15/20 Brazil A rafter is seen on the ground at a construction site for the monorail where one construction worker died and two workers were left injured after one of the rafters collapsed in Sao Paulo 16/20 Brazil The rafter in Sao Paulo collapsed due to unknown reasons 17/20 Brazil Subway train operators, along with activists from social movements, clash with riot police in front of the Ana Rosa metro station, in an ongoing subway strike, in Sao Paulo 18/20 Brazil Authorities are deeply worried about the strike because the subway is the main means of transportation for World Cup fans scheduled to attend opening match when Brazil takes on Croatia 19/20 Brazil A police officer pepper sprays strikers and protesters during a clash with riot police in front of the Ana Rosa metro station, in an ongoing subway strike by operators in Sao Paulo 20/20 Brazil Brazilian are furious over Christ the Redeemer statue in Rio de Janeiro dressed in a giant Italian football shirt for a television commercial

An investigation into the cause of the accident is under way, officials said.

The monorail was supposed to ease congestion in the city before the arrival of fans from around the world, linking the Congonhas airport with three metro lines.

But the metro system itself has been paralysed by a workers’ strike ahead of the tournament.

According to O Globo, the subway operator Metro issued a statement saying it “regretted the accident that happened during the work on monorail Line 17”.

The identity of the victim is yet to be released.

Brazil's preparations for the World Cup have been marred by accidents and missed deadlines.

Last November, two workers were killed when a crane fell into a corner of the Corinthians Arena, which will host the tournament opener between Brazil and Croatia from 9pm on 12 June.

Fans have already begun arriving in Sao Paulo for the World Cup, and were met with extensive traffic jams and long delays after police used tear gas to tackle striking metro workers, protesting over a pay dispute.

Union bosses announced that the strike would be suspended for today and Wednesday – and that a vote will be held to decide whether or not it resumes before Thursday’s match.