Catholic bishops in the Philippines are pitching in to seek divine relief from the extreme heatwave scorching the country, instructing their flock to recite special prayers for rain and lower temperatures.

Rising temperatures have forced the government to shut down tens of thousands of schools over the past week, while increased demand has stressed the country's already strained power supply.

A widespread El Nino drought that began early this year is compounding the problem, ruining 5.9 billion pesos ($103 million) worth of farm produce so far according to the Department of Agriculture.

The Catholic Bishops of the Philippines issued an "Oratio Imperata", instructing parishes in the mainly Catholic nation to recite a prayer for deliverance from calamities during masses, according to the text seen by AFP on Saturday.

"We humbly ask you to grant us relief from the extreme heat that besets your people at this time, disrupting their activities and threatening their lives and livelihood," the prayer read.

"Send us rain to replenish our depleting water sources, to irrigate our fields, to stave off water and power shortages and to provide water for our daily needs."

A record-high 38.8 degrees Celsius (101.8 degrees Fahrenheit) was recorded in the capital Manila on April 27, forcing the closure of more than 47,000 schools for two days.

Nearly 8,000 schools remained shuttered as of Friday, the education department said, while the highest temperature in the country was recorded at 38.2C on the island of Mindoro south of the capital.