Three people were killed and six others were still unaccounted for when an open pit coal mine in the central Philippines collapsed on Friday due to heavy monsoon rain, a local government official said.

Antique provincial governor Rhodora Cadiao told radio station dzBB that she had asked mine operator Semirara Mining and the Power Corporation to suspend operations until the buried workers were found.

"Three workers were found and brought to a hospital but they were declared dead on arrival," Cadiao said, adding rescue teams are using heavy equipment to recover the six people buried by the collapsed coal mine.

She said it was raining heavily for days on the mine site, on an island off the main island of Panay in the central Philippines. "The accident happened around 3 a.m. while the workers were working on a water system," said Cadiao.

There were only nine workers at the site when the accident happened, said Isidro Consunji, CEO of Semirara Mining & Power Corp, confirming they were buried alive by the landslide.

"Three bodies have been recovered as of this time and digging continues to look for six others," he said. "That's as far as I know. Some of our mining equipment has also been damaged. We don't have the complete details yet."

Semirara, a unit of Philippine conglomerate DMCI Holdings Inc, is the country's largest coal miner. The company may issue a statement later.

In 2013, five people died and five others were missing in a landslide in the coal mine on Semirara island.