Most Brazilian airports being upgraded for the 2014 soccer World Cup will not be ready on time, likely causing serious transport bottlenecks for fans, a government-backed research group said yesterday.

Only two of 13 airport terminals under expansion are on schedule to be completed by the time the tournament begins in June 2014, while a third might be ready, "if everything goes right," according to a study by Brazil's Institute for Applied Economic Research, or Ipea.

Brazil, which will also host the 2016 Summer Olympics, is scrambling to find investment to address severe infrastructure deficiencies -- from overcrowded airports and sea ports to poor roads and insufficient public transport in major cities like Sao Paulo and Rio de Janeiro.

"The situation is such that it's increasingly unlikely that these projects will be ready on time," said Carlos Campos, one of the authors of the study.

Brazil's government and Cup organizers promised to complete work on airports, stadiums and other related infrastructure as a condition of holding the tournament, the world's most popular sporting event.

The country's tourism ministry is expecting between 800,000 and 1 million visitors for the Cup.

Infraero, the state-owned airport authority, has budgeted 1.4 billion reais ($887 million) for upgrades to 13 airports in the 2011-2014 period. Nine airports, eight in cities hosting games and one that helps serve Sao Paulo, are behind schedule, Ipea said.

In addition to the 13 airports being upgraded for the Cup, a brand-new airport in Natal, another World Cup host city, still has no firm date for completion.

So many projects related to the Cup and Olympics are behind schedule that Pele, the Brazilian soccer legend, warned in February that Brazil risks "embarrassing itself.

Ipea put much of the blame for the delay on Infraero, which it said "has a low level of efficiency in the execution of investment programs." The study urged the agency to take swift action to improve its management.

Even if all 13 airport upgrades were to be ready on time, 10 are expected to be operating over capacity by the time of the Cup, Ipea said. Fourteen of Brazil's 20 largest airports are already operating at more than 80 percent of capacity.

Brazil will likely have to adopt temporary terminals with remote boarding facilities far from principal buildings to provide capacity needed to move visitors to the Cup and Olympics, the study concluded.