The won also slid ahead of the central bank's policy meeting on Thursday. The Bank of Korea is widely expected to leave policy interest rates unchanged this time, but many analysts anticipate that the next move will be a cut, a Reuters poll showed.
The Bank of Japan's unexpected easing on Oct. 31 accelerated the yen's weakness and prompted South Korea's top official including President Park Geun-hye to express concerns, as exporters from the two countries compete to sell similar products to major markets around the world.
The Malaysian ringgit lost as much as 0.5 percent to 3.3470 per dollar, its weakest since May 2010, as lower oil prices dampened sentiment toward Malaysia, due to its status as a net oil exporter and major palm oil producer.
The ringgit's weakness came even as industrial production in September rose 5.4 percent from a year earlier, beating market expectations.
The ringgit recovered some ground as the central bank was suspected of intervening to support the currency, traders said.
Indonesia's rupiah fell 0.4 percent to 12,195 per dollar, its weakest since Oct. 17.
Offshore real money funds and speculators sold the currency in non-deliverable forwards markets.