The new policy covering the 1,400 Metro Manila traffic enforcers was imposed following complaints about some personnel, said Yves Gonzales, director of the city's traffic discipline office.
"We got complaints that there were enforcers who were drinking on duty. Just three days ago, we received a complaint via Twitter that one enforcer smelled of liquor," he told AFP.
He said the tests would be conducted at random as the enforcers reported for duty.
But if the city authority received reports of a traffic cop drinking, the discipline office would deploy breath checkers to have the officer tested.
Those caught face a suspension of between one and six months for the first offence and dismissal for the second, he added.
The Philippine capital has some of the most densely packed and chaotic roads in Southeast Asia, with the average vehicle speed topping only about 10 kilometres an hour at peak times.
Traffic enforcers help to unclog the roads, especially when traffic lights fail or when vehicles get caught by a red light in the middle of a junction.