Vaiko also on Friday held talks with BJP president Rajnath Singh regarding the invitation extended to Sri Lankan President to attend Modi's swearing-in ceremony.
Tamil Nadu CM Jayalalithaa, who has raised the plight of Tamils living in Sri Lanka, is also reportedly upset with the BJP's invite to the Sri Lankan President.
The AIADMK supremo, who expressed dismay over reports that the Sri Lankan President had been invited and that he had accepted it, said it would have been better if this move had been avoided.
Vaiko and many other Tamil political parties allege that civilian casualties of the Tamils peaked during the last leg of the war against LTTE with Rajapaksa at the helm of affairs.
Karunanidhi's reaction comes after MDMK chief Vaiko and Tamil Nadu Chief Minister J Jayalalithaa expressed their apprehension over Modi's invitaion to Rajapaksa.
Heads of government of all eight SAARC countries, Sri Lanka included, have been invited to attend Monday's swearing-in ceremony of Modi as India's new prime minister. Besides Rajapaksa, leaders of the Maldives, Afghanistan and Nepal have accepted the invite.
With agency inputs