The Philippine peso turned higher, tracking regional appreciation, although the economy grew at its slowest pace in more than five years in the third quarter.
The lower-than-expected growth data forced the peso to reverse initial strength and end the morning session weaker. But it firmed again in the afternoon session.
The won rose as much as 0.8 percent to 1,098.1 per dollar in local trade, its strongest since Nov. 18, on increasing demand from exporters for month-end settlements.
South Korea's foreign exchange authorities were suspected of intervening to check the won's gains against the yen, traders said. The won touched 9.3353 to the Japanese unit, its strongest since August 2008.
The dollar eased against the yen as US data on consumers, housing and manufacturing pushed the benchmark 10-year Treasury note yield to a one-month low on Wednesday.
Malaysia's ringgit benefited from the dollar's weakness. The ringgit cut some of gains on concerns that lower oil prices may hurt economic fundamentals of the net oil exporters and major palm oil producer.
Some offshore funds sold the ringgit in non-deliverable forwards markets as oil prices fell, with Brent crude at a four-year low on views OPEC is unlikely to cut output during a meeting later in the day.