Rio de Janeiro mayor Eduardo Paes has vowed to punish those responsible for structural defects in the showpiece venue for the 2016 Olympic Games.
The Joao Havelange stadium was shut in March after an appraisal by an independent engineering firm showed the venue's roof could collapse due to structural problems.
Paes said construction of venue, built for the 2007 Pan American Games, had been "rushed at the last minute."
"I did not build this stadium but I do not want to shy away from my responsibility as mayor," Paes said on Thursday. "Things were done in the nick of time. We will establish who is responsible and the culprit will not go unpunished."
Paes said the German company that conducted the stadium's appraisal, Schlaich, Bergermann und Partner (SBP), was due to submit a report with structural solutions within 30 days. But he admitted it could take longer.
"We still don't have a solution," Paes said. "If it takes 90 days, I will wait 90 days."
Earlier on Thursday, structural engineering and consulting association Abece questioned the need to close the stadium and asked to see a copy of SBP's report.
But Paes rejected the claims, saying even the most minute risk to public safety warranted the decision.
"You cannot take any risks with this type of thing," he said. "If you have 20 reports and only one says it could collapse, I'll go with the one that says there is a risk of collapse."
The Joao Havelange stadium, known locally as the "Engenhao" after the neighborhood in which it is located, is set to have its capacity increased from 47,000 to 60,000 for track and field events at the Rio Olympics.
The revamped Maracana stadium, which will officially reopen for an international football friendly between Brazil and England on June 2, will host the Games' opening and closing ceremonies as well as the Olympic and Paralympic football tournaments.
Consorcio Engenhao, the building consortium responsible for the stadium, has denied any wrongdoing and says it is collaborating with the local government to find a quick solution.
The stadium's closure is one of a series of setbacks to affect Brazil as the country prepares for the 2014 World Cup and the 2016 Rio Olympics.
Two of the six stadiums redeveloped for next month's Confederations Cup -considered a World Cup warmup - are yet to reopen despite being given a December 2012 deadline by world football's governing body FIFA.
FIFA earlier this week expressed "concern" at the progress of Sao Paulo's World Cup stadium after officials said the venue would not be ready on time.