A sister of one of the three Indonesians detained in the Philippines on suspicion of terrorism has described their arrest as a "weird drama."

Nuraini Balfas was quoted by the Kompas daily Saturday as saying her brother Abdul Jammal Balfas and two other Indonesians – Tamsil Linrung and Agus Dwikarna – had not deliberately carried explosives in their luggage. They were "shocked" when officers at Manila airport found the items as they were about to board a commercial flight for Bangkok.

"At Ninoy Aquino airport several strange things happened and there the weird drama began," Balfas was quoted as saying by Kompas. Balfas said the trio's luggage had passed X-ray detector at the immigration gate when an officer looked at Dwikarna's passport and asked for the bags to be re-examined. Immigration officials found brown powder in Linrung and Balfas's bags and a piece of wire in Dwikarna's bag, Balfas said.

She said the trio's visit to Thailand and the Philippines was sponsored by a Thai businessman identified as Dr Prasan, who wished to invest in coal mining in Indonesia's West Kalimantan province and Mindanao in the southern Philippines.

Prasan, who was with the three when they were arrested at the airport, gave the detainees 5,000 dollars to hire Filipino defense lawyers and had met their wives in Indonesia to apologize, she said.

Several Indonesian Muslim groups have protested the arrests. Parliament deputy speaker Andi Fatwa told Kompas that the chief of the Indonesian Intelligence Agency, Abdullah Hendropriyono, had denied that the arrest of the three was based on a tip off from him.

Another MP, Ibrahim Ambong said Hendropriyono told him the three had no record of terrorist activity.

Philippine police have said all three had reportedly met associates of Fathur Rohman al-Ghozi, another Indonesian linked to a string of bombings in Manila on December 30, 2000 that left more than a dozen people dead.

Al-Ghozi, who was arrested by Philippine police in January, has allegedly admitted being a bomb expert working for Jemaah Islamiyah, an outfit touted as the Southeast Asian wing of Saudi militant Osama bin Laden's al-Qaeda network.