MANILA - PHILIPPINE authorities on Wednesday issued aviation alerts and warned nearby residents of possible mudflows as a restive volcano ejected more ash.

Booming sounds accompanied two ash explosions from the 1,565m Bulusan volcano on Tuesday, showering nearby communities with grey ash, the Philippine Institute of Volcanology and Seismology said in an advisory.

'Civic aviation authorities must advise pilots to avoid flying close to the volcano's summit as ejected ash and volcanic fragments from sudden explosions may pose hazard to aircraft,' it added.

Bulusan, 250km south-east of the capital Manila on the main island of Luzon, is one of the country's 23 active volcanoes.

People living near streams and valleys in the area were warned that mudflows of volcanic ash could be triggered by heavy rainfall.

The government has not ordered any evacuation, but said up to 75,000 people from the nearby towns of Irosin and Juban could be at risk if the currently mild eruption increases.

Philippine volcano spews ash