Rajapaksa, who faces elections on January 8 next year, had said that rights violations and allegations of war cirmes will be probed through domestic judicial processes.
The Sri Lankan President, who had not cooperated with a UN probe into allegations of rights abuse and war crimes, made the announcement a few days ago while releasing his party's election manifesto.
Criticising Rajapaksa for not consenting to an international probe into war crime allegations, Karunanidhi said, "Now when polls are round the corner, he says he is ready for a judicial probe."
Referring to Rajapaksa's appeal to Tamils to forget the past, the DMK chief said, "he, however, did not come forward to forge an electoral alliance with Tamil parties."
The "same Rajapaksa" had also promised earlier that recommendations of Lessons Learnt and Reconciliation Commission and 13th Constitutional Amendment will be implemented and Tamils bestowed with rights, he pointed out.