MSCI's index of Latin American currencies fell 0.8% with Chile's peso raking up the biggest losses.
Focus was also on Brazil's central bank meeting this week when officials are widely expected to cut record-low rates by 50 basis points in order to shore up Latin America's largest economy. The real fell 0.5%.
Colombia's peso shed 0.5%, while Mexico's peso traded flat after the government said it will uphold its pledge to keep fuel prices stable despite attacks on Saudi oil sites.
Stock indices in the region tread water with Mexico's IPC index the only notable gainer, up 0.3% as investors returned from a long weekend.
Oil prices dropped sharply after a Saudi Arabian source told Reuters that production could be fully back on line within weeks, quicker than initially thought, but sentiment was still fragile over the threat of retaliation for the attacks.
Investors were also on the fence ahead of the US Federal Reserve's two-day policy meeting beginning on Tuesday.