The Philippines has closed schools down and warned of overloading on its power grid, as authorities across Southeast Asia issued a series of health alerts for a deadly heat wave.

The Philippines' education ministry cancelled classes at public schools for two days on Sunday.

Temperatures in the Philippines are forecast to reach 37 degree Celsius in the next three days, with many classrooms crowded and without air conditioning.

The country's weather agency said the heat index - the actual temperature felt by the body to include relative humidity - is expected to remain at a record 45 degrees Celsius.

The heat wave is also putting pressure on power supplies on the main island of Luzon.

In Thailand, temperatures are forecast to surpass 40 degrees in Bangkok and the country's central and northern regions.

Temperatures soared to 44.2 degrees Celsius in the northern city of Lampang on April 22, with the meteorological department saying on Monday it expects the extreme heat will continue this week.

In the past month, 30 people have died from heatstroke, data from Thailand's health ministry showed.

People are seeking respite from the heat in air-conditioned shopping malls in Vietnam's business hub Ho Chi Minh City, state media reported, with the country's national weather agency warning of risks of forest fires, dehydration and heat shock.

Malaysia issued hot weather warnings on Sunday for 16 areas that have recorded temperatures between 35 and 40 degrees for three consecutive days.

In Singapore, the country's temperatures could soar higher in 2024 than last year, which was Singapore's fourth-warmest year since records began in 1929.

Singapore's hottest day recorded was May 13 last year when the highest daily maximum temperature hit 37 degrees Celsius.