South Korea's won slid against the dollar as the yen plumbed seven-year lows against the greenback, heading towards the 120 per dollar level.
Caution grew over possible intervention by the foreign exchange authorities to check the won's strength against the yen .
The won hit 9.2868 to the Japanese unit, its strongest since August 2008. South Korea and Japan compete to export cars and other products.
Indonesia's rupiah hit a six-year low on dollar demand from local corporates. The country's second biggest party on Wednesday re-elected tycoon Aburizal Bakrie as its chief for the next five years, dimming hopes that the opposition group would join President Joko Widodo's minority coalition.
The rupiah later pared most of the day's losses with the central bank spotted intervening to limit the currency's slide.
Malaysia's ringgit fell to 3.4475 per dollar, its weakest since February 2010, on sustained concerns that lower oil prices may hurt economic fundamentals of the country, a net oil exporter.
Bearish bets on the ringgit rose to their highest since September 2008, a Reuters poll showed earlier.