Bangko Sentral ng Pilipinas Governor Amando Tetangco, who has said he was ready to ease policy if growth slowed, on Tuesday forecast annual inflation in December in a range of 4.0-4.9 percent.

That forecast is based on a data series using 2000 prices, which will be phased out after this year. Inflation was 4.7 percent in November and 5.3 percent in October under the series.

A new inflation series, using 2006 as its base year, showed annual of 4.8 percent in November and 5.2 percent in October.

"The outlook for inflation remains manageable as we continue to see within-target inflation over the policy horizon," Tetangco said in a mobile text message to reporters.

"Nevertheless, the BSP remains watchful of global developments to ensure that our policy settings remain appropriate."

An inflation rate below 4.3 percent, calculated under the old series, would be the lowest since January 2011 when the rate was 3.6 percent.

The central bank's policy rate has been at 4.5 percent since May and some analysts expect cuts of as much as 50 basis points in the first half of 2012.

Tetangco has said the central bank was willing to ease monetary policy by cutting interest rates, reducing the reserve requirement ratio, or both to support economic growth as long as inflation in the country remained under control.

At its Dec. 1 policy review, the central bank raised its average inflation forecasts for this year out to 2013, but they remain well within the 3 to 5 percent target.

Policymakers believe the impact on prices from crop and infrastructure damage caused by a typhoon that hit the southern Philippines this month will only be temporary, and that inflation should ease into 2012.