Tamil Nadu Chief Minister K Palaniswami on Friday said a bill passed by the Sri Lankan Parliament is a setback to diplomatic efforts being made by India and the island nation to amicably resolve fishermen's issue.

In a letter to Prime Minister Narendra Modi, the Chief Minister demanded that the Indian government register protest with Sri Lanka over the alleged passage of the Fisheries and Aquatic Resources (Amendment) Bill and also ensure that the rights of Indian fishermen in the Palk Bay are defended.

According to the text of the letter released to the media here, Palaniswami said: "The passing of the ill-advised Bill at a time when the Ministers of India and Sri Lanka as well as the Joint Working Group on Fisheries have met recently to resolve the India-Sri Lankan fishermen's issues is shocking."

"Sri Lankan government's unilateral move will definitely hamper joint initiatives taken by both countries. The legislation is, in fact, a severe setback to diplomatic efforts to resolve the issue amicably," Palaniswami said.

Citing reports, the Chief Minister said under the Bill, fishing trawlers and other gear used for fishing in Sri Lankan territorial waters will be confiscated, erring fishermen imprisoned for two years, and huge fines of up to 50,000 Sri Lankan rupees will be imposed.

The Bill allegedly is predominantly aimed at Indian fishermen, who have been fishing in the Palk Bay for centuries.

"As you are aware, the Palk Bay is a historic and traditional fishing area of Indian fishermen from Tamil Nadu. The historic rights of Indian fishermen were simply signed away as part of the ill-advised India-Sri Lankan agreements of 1974 and 1976, which also unilaterally ceded Katchatheevu to Sri Lanka without any foresight or concern for the plight of our innocent fishermen," Palaniswami added.

He said 50 Tamil Nadu fishermen and 143 fishing boats belonging to Tamil Nadu fishermen are in Lankan custody since 2015.

The new legislation is aimed at preventing our fishermen from exercising their traditional fishing rights in waters they have continued to fish for several centuries and will deny their fundamental rights conferred by the Constitution of India, the Chief Minister said.

"Thus, the government of India should register its strongest disapproval of such a move," Palaniswami said.