Traders are worried that the US Congress and President Barack Obama may fail to reach a deal on raising the US government's borrowing cap by an Oct. 17 deadline, which could lead to the risk of a US default and cause turmoil in financial markets.
Such jitters have helped weigh on Asian currencies, which have taken a breather in the wake of last week's broad rally against the dollar.
Their declines on Tuesday were led by the South Korean won and the Malaysian ringgit.
The Indonesian rupiah held steady on the day, showing little reaction after Indonesia's central bank left its benchmark reference rate unchanged at 7.25 percent as widely expected.
After having raised the benchmark rate by a total of 150 basis points since May, the central bank had been expected to stand pat on Tuesday, as recent encouraging data improved market sentiment and eased pressure on the rupiah.
The US dollar has gained a bit of respite in the past couple of days after its broad drop against Asian currencies last week.
Speculation that the US government's partial shutdown could become protracted and lessen the chances of the Federal Reserve scaling back its monetary stimulus in the near term had helped knock the greenback lower last week.