The positive effect of the peso appreciation has significantly contributed to softening the impact of high international oil prices, said Melinda L. Ocampo, Undersecretary and Officer-in- Charge of the Philippine Department of Energy (DOE). 

Net increase of the local pump prices since the start of this year is only 1.20 pesos per liter for diesel and 2.20 pesos per liter for gasoline, the DOE official told reporters with a press release. 

The average hike in the international market during the same period is 10 U.S. dollars per barrel in the prices of diesel and 20 dollars in the prices of gasoline, according to the press release. 

The Philippines' local pump prices are also way below the peak prices in August 2006, which were 37.75 pesos per liter for diesel and 44.25 pesos for gasoline, the DOE added. 

"Oil price increases would have been much higher without the peso appreciation. If the peso were not as strong as it is today, the impact would have been much higher," Ocampo said. 

Average price of unleaded gasoline in world market has increased by about 5.39 U.S. dollars from April to 89.03 U.S. dollars per barrel in May, while average price of diesel in May is now at 83.42 U.S. dollars per barrel compared to 82.11 U.S. dollars per barrel in April, the DOE said. 

Meanwhile, the peso has appreciated against U.S. dollar from the average exchange rate of 47.82 in April to 46.95 in May.