Crowds are flocking to see a Buddhist temple in central Thailand exposed after drought drove water levels to record lows in a dam reservoir where it had been submerged.

Wat Nong Bua Yai is a modern temple that was submerged during construction of the dam 20 years ago.

As the reservoir reaches less than 3% of capacity, the remains have became visible in the middle of dry ground.

Some Buddhist monks were among the hundreds of people who walked through broken temple structures on cracked earth last week to pay respects to a headless four-metre tall Buddha statue.

"The temple is normally covered by water. In the rainy season you don't see anything," said one of the visitors.

He regretted the temple flooding but is now worried about the damage the drought is causing to farmland, he added.

The dam, with capacity of 960 million cubic metres, normally irrigates more than 1.3 million acres of farmland in four provinces.

However, the drought has cut that to just 3,000 acres in the single province of Lopburi.

Thailand is facing its worst drought in a decade, the meteorological department said. Water levels in dams nationwide have fallen far short of the monthly average.

The ruins also reappeared following a drought in 2015.