SINGAPORE -- Most Asian currencies fell Thursday against the broadly firmer US dollar after the Federal Reserve opted to refrain from buying government debt, but the South Korean won jumped, helped by foreign buying of local stocks.

Trading activity remained lackluster as markets in China and Taiwan were shut for holidays.

The Philippine peso fell as far as 47.14 per dollar, down almost 0.5 percent from Wednesday's close, with little support from official data showing the economy grew a stronger-than-expected 4.5 percent in the fourth quarter.

Despite the positive surprise, the central bank is expected to cut interest rates by 50 basis points later in the day to spur growth.

"The dollar is strong across the board," said a Manila-based trader, who expected the peso to get some support from the rate cut.

"I'd probably look at it (the rate cut) as a positive thing -- it's good for corporates and also good for stocks," said the trader.

Asian stocks climbed as investors took heart from the US Congress making headway on a $825-billion stimulus package and other efforts to stem the financial crisis.

Rising stocks failed to help most Asian currencies with the exception of the volatile won, which rose almost 1.6 percent to 1,354.9 per dollar as Seoul shares rose, driven in part by foreign buying.

The won is still down 7.8 percent against the dollar this month after losing 25 percent in the whole of 2008.

The dollar held firm against a basket of currencies, a day after the Fed kept interest rates steady near zero and refrained from buying long-dated Treasuries for now.

Worries that the Fed's effort to boost its balance sheet will devalue the world's top reserve currency have dogged the dollar since the rates were cut to virtually zero in December.

The Malaysian ringgit was also down 0.5 percent to 3.6030 per dollar, while the Singapore dollar lost about 0.3 percent to 1.5060 to the US dollar as investors fretted about the country's economic outlook.

"There is a lot of outright buying of the US dollar by offshore players, as they see the Singapore dollar weakening further based on Singapore being an open economy and very exposed to this crisis," said a trader in Singapore.

Last week Singapore announced a S$20.5 billion ($13.7 billion) stimulus package to help companies and save jobs as the economy sank deeper into recession.

The Singapore dollar has lost 4.7 percent against the US dollar this month, the second worst performer after the South Korean won.

The Monetary Authority of Singapore steers monetary policy by managing the Singapore dollar's trade-weighted nominal effective exchange rate within a undisclosed band.

Olivier Desbarres, currency strategist at Credit Suisse, said he expected the Singapore dollar to hit 1.55 per US dollar in three months as he expected the authorities to lower the centre of the band in April by around 2.0 percent, effectively cancelling out the April 2008 revaluation.