The incident took place during a Jehovah's Witnesses convention at the center in Kalamassery, about 10 kilometers (6.21 miles) northeast of Kochi.
Kerala Chief Minister Pinarayi Vijayan said the incident was very unfortunate and that the police have taken it very seriously, Reuters reported.
He said police are collecting the details and cannot provide further details now.
P. Rajeev, Kerala's industry minister, told reporters that the cause of the explosion could not be immediately determined.
"A detailed investigation is on. The reason can be known only after the investigation," he said.
Local newspaper Mathrubhumi said at least three explosions occurred inside the convention hall, with more than 23 people injured. The injured have been rushed to hospitals.
AMK/PR