SÃO PAULO — Brazil’s government emphatically refused on Tuesday to suspend work on a huge hydroelectric dam in the Amazon, despite pleas that the project could displace tens of thousands of indigenous people and cause environmental harm.

The Inter-American Commission on Human Rights, part of the Organization of American States, ’had asked Brazil on Friday to halt construction of the Belo Monte dam, slated to be the world’s third largest, until it complied with its legal obligations to consult with indigenous groups.

The commission said the consultations needed to be “free, prior, informed, of good faith and culturally appropriate.” Among its requests were measures to prevent the spread of diseases that could result from the population flow during construction.

But on Tuesday Brazil’s Ministry of Foreign Affairs ’called the demands “premature and unjustified,” saying the government had complied with its obligations under Brazilian law.