The agency warned the residents of Luzon Island to stay clear of the volcano in a 4.3-mile-wide radius.
Access to the danger zone is restricted in parts of Agoncillo, Laurel and Batangas.
According to the UN Office for the Coordination of Humanitarian Affairs, about 486,000 people have been affected by the erupting volcano since January 12.
On Friday, the fiery mountain sitting in the middle of Taal Lake was coughing up plumes of dirty steam and smoke.
The volcanic plumes were seen reaching heights between 1,640ft and 2,296ft, drifting in a southwest direction.
At the same time, PHIVOLCS said emissions of toxic sulphur dioxide (SO2) have dropped below instrumental detection.