Inadequate infrastructure, particularly in air transport, threatens soccer-mad Brazil's hopes of dazzling the world with the best-organized World Cup ever 12 months from now.

Expectations are high. It will be the first World Cup hosted by the South American powerhouse since 1950, when the country's defeat to Uruguay in the final at Rio's iconic Maracana stadium is still considered a traumatic national humiliation.

Brazilians may not have invented soccer but they have elevated it to an art.

Some 355,000 Brazilians and foreign tourists are expected for the tournament. But organizers have been struggling to complete the construction or renovation of the six host arenas, with construction work plagued by repeated delays due to strikes, roof collapses and other problems.

Four of the stadiums were delivered to soccer world governing body FIFA behind schedule and in the northeastern city of Salvador last month "a human error" caused part of the roof of the brand new Arena Fonte Nova to collapse following heavy rains.

In a vast country bigger than the continental United States, transport is a huge challenge.

Traffic jams can stretch up to 200 kilometers (124 miles) in major cities, roads are often in a sorry state, while airports are congested and there is virtually no passenger train service.

Air transport has increased more than 120 percent over the past decade, on the back of rising disposable income but airport capacity has been overwhelmed.

The country's notoriously congested airports now have to cope with an influx of three million Brazilian tourists and 500,000 foreigners who will flock to the 12 host cities during the World Cup.

Some airports have been privatized and others have slowly been upgraded.

But critics say investment in infrastructure has been insufficient.

"Without good planning, good regulation and investment incentives, it (the World Cup) is going to be a disaster," Gesner de Oliveira, an infrastructure expert at the private Getulio Vargas Foundation (FGV) business school in Sao Paulo, warned.

Brazil spends roughly two percent of its gross domestic product on infrastructure compared with more than seven percent by China and five percent by Chile, he noted.

Nevertheless, Oliveira believes emerging Brazil "can make a great leap forward and rise to the occasion by staging a decent World Cup in terms of infrastructure."

Just boosting the capacity of airports will not be enough, however, "if they cannot operate satisfactorily, if you have endless queues, delays in luggage handling," sports minister Aldo Rebelo said recently.

While FIFA is banking on $4 billion in revenue from the World Cup, including 60 percent from television broadcasting rights, the Brazilian government is earmarking $15 billion in public investments for the event.

A joint study by consulting firm Ernst and Young and FGV says these investments mean that $70 billion are being pumped into the national economy.

"Brazil's biggest challenge is not building stadiums, metros, airports or telecommunications, but rather how to make the best use of these investments," Pedro Trengrouse, the United Nations official monitoring the World Cup, said.