The decision has been taken after the Asom Gana Parishad appealed to the Shiv Sena to oppose the legislation, party leader Sanjay Raut said in a statement.
“We are determined to oppose the Citizenship Amendment Bill 2016 in Parliament,” Raut said.
The people of Assam, irrespective of their caste, religion and creed, oppose the proposed legislation, he said.
The bill seeks to amend the Citizenship Act to make illegal migrants from Afghanistan, Bangladesh and Pakistan eligible for citizenship on the basis of religion.
The Joint Parliamentary Committee examining the bill is slated to table it in Parliament on January 7.
The Shiv Sena noted that the proposed legislation would “frustrate” the efforts made under the Assam Accord for safeguarding cultural, social and linguistic identity and heritage of the Assamese people.
Secondly, the entire process of the National Register of Citizens monitored by the Supreme Court will be meaningless if the bill is passed, he added.
With the Lok Sabha polls around the corner, the Shiv Sena has adopted a more aggressive posture against the BJP, with whom it has shared an uneasy relationship over the past four years.