"Chidambaram is being targeted by the Central government for writing and speaking against it," he said.
Central investigating agencies are now "entering and searching" the premises of political leaders "without any evidence," Mr Narayanasamy told reporters at the airport.
The senior Congress leader said people not just in Tamil Nadu but across the country were well aware about Mr Chidambaram, and recalled that the latter had held the Home and Finance portfolios during the UPA regime.
"He is a clean politician. No one can make an accusation against him. Since he is speaking against the Narendra Modi government in parliament and writing against it, cases are being filed against his family (Karti) with a view to malign his reputation. This will never happen," he said.
On May 16, the CBI had searched the homes and offices of Karti across four cities for allegedly receiving money from a media firm owned by Indrani and Peter Mukerjea to scuttle a tax probe, a charge denied by him.
On Karti's London travel, Mr Narayanasamy said the CBI or the Enforcement Directorate had not barred him from undertaking such a journey.
The chief minister said BJP was "trying to create confusion" in Tamil Nadu and said the party had no base in the state.
Whether by itself or with the help of an alliance, the party cannot prosper in the state, he said.
Mr Narayanasamy also lashed out at the BJP government at the Centre for its handling of various issues, including the Cauvery dispute and farmers issue, adding this had resulted in the suffering of people of both Tamil Nadu and Puduchery.