Acting on a tip-off, a team led by Customs Superintendent Kalidass seized 110 kgs of ganja from Singili Theevu and Manozhi Theevu, officials said.
They said the ganja was meant for being smuggled to Sri Lanka and worth over Rs 50 lakh in the street market.
Further investigation was on to find out who brought the narcotic stuff to the islets, they added.