The decision was taken by the party state committee, acting on the directive from the central committee which had recently asked the state unit to take further action against Mani, party sources said.
Mani was earlier removed as CPI(M) Idukki district secretary after his speech, in which he had stated the party had in Idukki drawn up a list of foes to be eliminated in the 1980s and three of them were done to death, caused huge embarrassment to CPI(M).
Ironically, Mani had made the speech at a public meeting called to explain to party workers that CPI(M) had no role in the murder of Marxist rebel and Revolutionary Marxist Party leader T P Chandrasekharan.
Several local and district-level CPI-M leaders had been arrested in connection with the murder case.
A criminal case had been registered against Mani against the backdrop of his "revelation" and his plea to quash the charges was rejected by Kerala High Court and Supreme Court.
When his reaction was sought, Mani told reporters that it was for state secretary Pinarayi Vijayan to say something on that but he would continue to work for the party.