Mr Vijayan also said Mr Mani had not tried to create "any hurdle" during the anti-encroachment drive on government lands in Idukki.
"Before law, there is no consideration as MLA or minister. There were complaints. A probe was held and no material was found warranting registering of a case against Mani," Mr Vijayan said during question hour in the state assembly.
Mr Mani had recently courted controversy when he allegedly made some offensive remarks against activists of 'Pembilai Orumai', a women's collective of plantation workers of Munnar.
The minister had also allegedly stated Devikulam sub-collector Sreeram Venkataraman should be sent to 'Oolampara' (asylum) for removing a 30-feet cross put up allegedly on an encroached piece of government land in Munnar last month.
Congress MLAs-- V D Satheeshan and P T Thomas-asked the government the reason for not registering a case against Mani for his comments against women workers and the IAS officer.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)