Officials who reviewed work on a television tower in the Olympic park and digging work at the Olympic village shut down operations at those and two other sites. They did not say exactly what the problems entailed or how serious they were.
"We have no intention of hampering the event," Robson Leite, the ministry's regional superintendent, told reporters. "We just want the safety of the population, the workers and all those who will visit Rio."
The Olympic Park, where 16 sports will take place at nine venues, was declared open last month but final touches to the tennis courts and sponsors' areas are still being made. The games open on August 5.
The city's oversight agency said it had immediately complied with the ministry's order.
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"Two areas where digging took place were cordoned off and a meeting will decide what adjustments are necessary so work can continue," the Geo-Rio Foundation said in a statement.
Such injunctions are common in Brazil and are usually quickly resolved.
However, Leite reminded reporters of a ministry study released last week showing that at least 11 people have been killed while working on Olympic projects, compared to eight in the 12 cities preparing to host the 2014 World Cup, which was also held in Brazil.
The shut down came just weeks after a bicycle lane built as part of the legacy infrastructure collapsed into the sea killing two cyclists.
(Reporting by Rodrigo Viga Gaier, writing by Andrew Downie; Editing by Mary Milliken)
