The CPI will file a petition before the Supreme Court, challenging the constitutional validity of the Citizenship (Amendment) Act, the party said on Wednesday.
The petition will be filed by its general secretary D Raja, a statement from the party said.
According to the amended Act, members of Hindu, Sikh, Buddhist, Jain, Parsi and Christian communities, who have come from Pakistan, Bangladesh and Afghanistan, till December 31, 2014 facing religious persecution there, will not be treated as illegal immigrants but given Indian citizenship.