More than 100 students were hospitalised after fainting 'due to extreme heat' during a school fire drill in the Philippines.

Some 3,000 pupils of the Gulod National High School in Cabuyao City, Laguna province participated in the emergency simulation at around 2:30 PM on March 23.

They were allegedly told to gather at an open field, where they were exposed to the harsh afternoon sun for more than 30 minutes. Not long after, dozens of youngsters complained they couldn't breathe before collapsing in the blistering heat.

Ambulances took the stricken children to two nearby hospitals for treatment. Cabuyao Police said in a report that around 120 students needed urgent medical attention.

One female student who declined to be named told local media: 'There was no roof. All of us were just staying there in the heat, and it was also cramped. We were not even allowed to stand and leave our place.'

Doctors said the pupils suffered heat exhaustion and dehydration. The recorded heat index in Cabuyao City that day hovered between 39 to 42 degrees Celsius, a disaster management official said.

Dr. Aliana Andino of the Cabuyao City Hospital said: 'When we checked them, they were hyperventilating, and some were dehydrated. Others had trouble breathing, so we rushed them to the resuscitation area to be given oxygen.'

Meanwhile, the local disaster risk reduction management office and the city fire department both said school management did not coordinate with them to hold the fire drill.

The Cabuyao City government said it will shoulder the students' medical expenses.

Cabuyao Mayor Dennis Hain said: 'These drills should be well-organised. We should coordinate with the disaster agency and the fire department, especially since they are the experts. If something goes wrong, the kids might be put at risk.'

Meanwhile, the regional Department of Health Office said it will look into the surprise fire drill.

Philippine weather bureau PAGASA said the Philippines has entered its dry season on March 21, cautioning locals to protect themselves against heat stress in the tropical country.