Central banks in South Korea and Indonesia have stepped into the currency markets in a bid to stabilise their currencies and stem falls.
The Korean won has declined by 10% against the US dollar in the past month, and the Bank of Korea said it was taking appropriate steps to stem the falls.
The BBC reports similar action was taken by the Indonesian central bank on Thursday to shore up the rupiah.
Analysts said big currency fluctuations were a threat to these economies.
