In a statement, the CPI(M) Politburo contended that a political party was a voluntary association of citizens who believe in the ideology, programme and the leadership, and it was accountable only to its membership.
It also asked the government to discuss the "serious implications" of the CIC order with all political parties so that suitable steps can be taken to preserve the integrity and the role of political parties in a democratic political system.
The CPI(M) said opponents of a political party can utilise the RTI as an instrument to destabilise a party.
"The CPI(M) cannot accept the order of the Central Information Commission that political parties are to be treated as "public authorities" and brought under the purview of the Right to Information Act. This decision is based on a fundamental misconception about the role of political parties in a parliamentary democracy," the statement said.
"Already under the RTI, the statement of accounts and the finances of the parties are accessible to anyone from the Election Commission. Any more details of the financing of the Party can be sought for and has to be given," it said.