"He (Mukherjee) himself knows I have the opinion that there should be no capital punishment," he told reporters here responding to queries whether he would convey his view regarding capital punishment to the President.
The question apparently referred to the mercy pleas of Murugan, Santhan and Perarivalan who have been sentenced to death for their alleged role in the assassination of the former Prime Minister by an LTTE suicide bomber in 1991.
Mukherjee's predecessor Pratibha Patil had rejected the mercy petitions of the trio, following which they have moved the high court.
"Now only he has come (sworn-in as President.) I will talk to him at the right time," Karunanidhi said.
The DMK chief said he would call on Mukherjee, who had launched his Presidential campaign from Tamil Nadu, when he visits Delhi.
He dismissed as "false" reports in a section of vernacular media that NCP supremo Sharad Pawar, whose party buried differences with ally Congress, had spoken to him on forming a Third Front.