FIFA officials, while confident that all work will be completed on the venues to be used in the 2014 World Cup, are concerned with the pace of construction with less than 50 days left until the opening ceremony.

FIFA secretary general Jérôme Valcke visited Sao Paulo's Itaquerao Stadium (also know as Arena Corinthians) -- which is slated to host the June 12 opening ceremony and opening match between Croatia and Brazil, Arena da Baixada in Curitiba, and Arena Pantanal in Cuiaba -- where the official inauguration of the facility, scheduled for over the weekend, has been canceled.

"I can tell you that it will be a very tight schedule over the next weeks in order to be ready for the opening game, and more important, to be ready on time for us to test the stadium," said Valcke to the Associated Press after his inspections.

With less than 50 days left until the start of the World Cup, Itaquerao Stadium will host only one event as a test for FIFA officials to make last-minute assessments on the facilities -- a Brazilian league match set for May 17 or May 18 which has only sold 50,000 tickets with the World Cup opener expected to host 70,000 people. FIFA normally prefers to run three events as "soft openings" to gauge last-minute accommodations and repairs.

Construction at Arena da Baixada stadium and Arena Pantanal is also facing problems with Valcke unhappy that 27,000 seats at Arena da Baixada stadium have yet to be installed while Arena Pantanal is missing 5,000 seats due to delays in their delivery.

FIFA has sold 2.7 million tickets and expects to sell a total of 3.3 million despite Brazil's failures to complete the massive stadium projects they promised the global soccer governing organization during the bidding process.

"We are working with Brazil to make the 2014 World Cup a successful reality," said Valcke. "We owe this to the 2.7m fans who have bought tickets to date."

FIFA organizers had threatened to strip the city of Curitiba of its World Cup host duties due to the severe lag in the reconstruction of Arena da Baixada, while the mayor of Porto Alegre, Jose Fortunati, had to corral local government officials into passing a bill creating tax incentives for companies investing in building temporary structures around Estádio Beira-Rio. Fortunati said that organizers fell short on funds to build housing for fans and sponsors as well as fulfill other FIFA requirements such as upgrading telecommunications infrastructure needed for media.

Because of Brazil's reputation for spotty service, telecommunications companies working with organizers had asked for 120 days to install and calibrate networks on the six new facilities promised this year. But World Cup organizers in Sao Paulo and Curitiba gave the telcom companies 70 days, in some cases, to improve coverage.

"We don't want Brazil to be remembered as the worst World Cup of all time because the journalists could not get their stories out to the rest of the world," said Valcke.

Venue construction has been further hampered by protests throughout the country, with as many as a million people taking to the streets ever since last year's Confederation Cup tournament -- a dress rehearsal for the World Cup. Brazilian tax payers are upset about ponying up a large chunk of the $10.9 billion bill to host the World Cup, with the private sector picking up only 15 percent of the tab despite promises to cover cost overruns. Stadium construction alone has ballooned to three times over the proposed budget, money that could have gone towards education and much-needed infrastructure.

The Brazilian government has created a special riot unit -- 10,000 deep chosen from the state police forces -- that will be mobilized throughout the country during the tournament should problems arise.

But organizers have fallen short recruiting and training private security guards that FIFA requires as a condition to host the tournament, with only 20 percent of the 25,000 recruits the Local Organising Committee requested having attained the certification needed to be completed by May 25 in order to provide security at the venues hosting the matches.

"The committee is overseeing this work and we are relaxed about that," Hilario Medeiros, head of security at the Local Organising Committee said to BBC Brasil. "If there is not enough private security [during the tournament], we will use public security, armed security. But we are working to make sure we will not have this problem."

Despite unfinished projects -- particularly with infrastructure for fans to get to the venues and hotel space -- and blown deadlines, officials feel confident everything will be complete in a timely fashion as soccer fans from around the world get ready to descend on Brazil.

"It's clear to us that there is a lot of work to do and that we can't waste a minute," said Sao Paulo vice mayor Nadia Campeao. "It's a tight schedule but it's all doable."