The currency had weakened 0.6 percent on Wednesday after Moody's Investors Service downgraded the country's long-term debt rating by two notches to four levels below investment grade, citing high public debt and slow fiscal reforms.
Analysts said the downgrade did not recognise the efforts the government had made this year to raise new taxes and cut the fiscal deficit.
"Moody's is behind the curve. Things are looking better in terms of economic recovery," said Jimmy Koh, head of treasury research at Singapore United Overseas Bank. "With the recovery, the fiscal position should improve."
The Thai baht weakened as much as a third of a percent to 38.60 per US dollar on renewed violence in the southern provinces where Prime Minister Thaksin Shinawatra was on a visit.
The South Korean won was steady at about 1,025.5 per dollar as traders ignored a finance ministry official's comment that the currency was overvalued against the dollar.
"The economy there is looking up," said Koh. "I don't think it's a fair statement that the won is overvalued. That's why the currency market didn't respond."
South Korea's finance minister said earlier on Thursday that growth in exports in the year to February was expected to be resilient and domestic demand had moved beyond its low point.
The premium on 12-month yuan forwards rose to price in a 3.9 percent gain in a year, up from 3.7 percent on Wednesday, according to Prebon Yamane prices. That compared with expectations of a 6.4 percent gain at the end of last year.
"We have maintained that progress in banking reforms is a key indicator for China's readiness for a change in the foreign exchange regime," said Cheung. She advised clients to buy yuan forwards against the dollar if the premium fell.
Separately, Malaysia said Thursday the country's six-year-old peg of 3.8 per dollar remained fundamentally sound and short-term capital inflows would not spark a change in the fixed-rate regime. Expectations of a ringgit revaluation were trimmed after the remarks. One-year ringgit non-deliverable forwards were quoted at 3.715/3.74 per dollar, compared with 3.70/3.71 on Wednesday.