With oil prices at crippling highs, the project would convert cars in the Makati financial district to run on a mix of 40 percent diesel and 60 percent cooking oil, its police chief Senior Superintendent Gilbert Cruz said.

Used cooking oil will be donated by Makati outlets of the hamburger giant, said McDonalds franchising manager Buth Salaya.

Other restaurants are also considering donating their used cooking oil as well, Cruz said.

One police car has been converted to use the diesel/cooking oil mixture and is already in use, and the government is studying how viable it is to convert more vehicles.

"It's a win-win situation for us because we will both benefit," Cruz said. "The cooking oil of their Makati stores will be re-used and the Makati police will use it as a component for their biodiesel and also save money."

The head of police forces in the capital Manila, Geary Barias, said that if the project is successful, he may recommend it being adopted by police forces across the Philippines.