The peso fell to a low of 51.71 per dollar from Thursday's close of 51.495. The currency, Asia's best performer in 2005, has failed to strengthen beyond the 51.0 per dollar level despite breaching that mark three times since March.

Dealers in Manila said growing dollar demand from crude oil importers, eager to lock in costs after crude prices surged to record levels above $ 72 per barrel this week, was the main driver for the peso's weakness.

''The crude prices are exceedingly high and oil companies are covering. The market is anticipating they may have more bills to pay,'' said Marcelo Ayes, a currency trader at Equitable PCI Bank in Manila.

Ayes said seasonal remittances from Filipinos working abroad are only due from May and until then, the peso is likely to remain under pressure particularly if oil companies step up dollar buying to pay for imports at the month-end.

Some dealers in Manila said the central bank was suspected of selling dollars at 51.65/70 levels on Friday, providing some support for the peso, while others said the central bank was unlikely to intervene as long as the moves were gradual.

Lito Biacora, chief currency dealer at the Bank of the Philippine Islands, said that besides dollar demand from oil companies, demand for dollars from banks after a decline in local treasury bill yields was also putting some strain on the peso.

''They're not happy with the market pushing t-bill yields lower,'' said Biacora.

Biacora and Ayes said they saw the peso's weakness as a short-term correction until remittances from overseas workers start flowing in from next month to cushion the impact of soaring oil import bills.

Using the Fibonacci retracement indicators on the peso's high and low for the year, they said the Philippine currency could get some support at the 51.75/80 levels.

''If that level is breached we'll see more weakness,'' said Biacora. ''But until then the trend of the peso strength this year is still intact.''