Exact details of the incident that led to the death of Fabio Hamilton da Cruz at Arena de Sao Paulo on Saturday have not been confirmed, but it has been reported he fell while working on the installation of seats at the ground.
Da Cruz's passing is the latest of several accidents which have marred the build-up to this year's showpiece event in Brazil, with two workers having died when a crane collapsed at the same stadium last November.
There have also been fatalities in Manaus and Brasilia and FIFA lamented the latest tragedy in a statement on their website.
"FIFA and the Local Organising Committee (LOC) deeply regrets the death of the worker Fabio Hamilton da Cruz after an accident that occurred on Saturday (29/3) at the Arena de Sao Paulo," it read.
"It is with great sadness that we send our sincere condolences to his family and colleagues.
"For LOC, FIFA and Brazilian officials, safety is paramount. We will wait for the official report from the authorities."
Concerns were this week raised over whether Estadio Beira-Rio in Porto Alegre will be ready in time to host matches and FIFA have come in for criticism for failing to ensure stadiums are completed with just over two months remaining until the tournament starts.
FIFA secretary general Jerome Valcke took to Twitter to express his sadness at the latest incident.
"Deeply saddened by the tragic loss of a worker at Arena Sao Paulo today. My thoughts and condolences are with his family & colleagues," he tweeted.
Brazil face Croatia at Arena de Sao Paulo in the opening game of the tournament on June 12.
