The stadium due to stage the opening match at next summer's World Cup will be the subject of urgent safety checks after two construction workers died in an horrific accident.
FIFA president Sepp Blatter expressed his sorrow and the world governing body pledged, along with the Local Organising Committee, to carry out a thorough investigation into how a crane collapsed.
The accident occurred when the crane that towered over the Arena Corinthians was lifting into place a final part of roof covering the north stand in what will become a 68,000-capacity venue and a new home for the Corinthians club.
Corinthians confirmed the deaths on their website, in a joint statement with the constructors.
The statement said: "Odebrecht Infrastructure and Sport Club Corinthians Paulista regret to inform you that in early afternoon an accident during work at Arena Corinthians caused the death of two workers - Fabio Luiz Pereira, 42, driver/operator of the company BHM Munck, and Ronaldo Oliveira dos Santos, 44, builder from the company Conecta.
"Shortly before 1300, the crane that hoisted the last part of the structure of the metal roof of the stadium collapsed."
A large crack was apparent in pictures of one of the stands that already had its roof fitted.
However, the joint statement added: "The structure of the grandstand was not compromised. It was the 38th time this type of procedure had been performed during the work."
Hosts Brazil are due to play in the opening match at the stadium on June 12, 2014, against opponents to be determined at next month's draw. It is also due to stage five further matches, including a semi-final.
FIFA president Blatter said on Twitter he was "deeply saddened" by the deaths.
In a statement, FIFA added: "The safety of workers is the top priority for FIFA, the LOC, the federal government. We know the safety of all workers has always been paramount for all the construction companies contracted to build the 12 FIFA World Cup stadiums. The local authorities will fully investigate the reasons behind such a tragic accident."
Corinthians announced the club would respect seven days of mourning for the victims of the tragedy, and according to reports in Brazil construction workers have been given leave for the next two days.
Odebrecht reported earlier in November that the World Cup venue was 94 per cent finished. It said on its website that 1,500 workers were involved in the construction, with the focus having turned to the final details of the project.