Explosions sparked a fire at a chemical factory in Thailand which killed 12 people and wounded more than a hundred.

Thai authorities are investigating the fire at the sprawling Map Ta Phut complex in Rayong - one of the world's biggest petrochemical hubs.

Thousands of residents and workers were evacuated from the area - some 180 kms east of Bangkok.

Thai Prime Minister Yingluck Shinawatra paid a visit to the patients in hospital.