Namal Rajapaksa is the son of former President Mahinda Rajapaksa, the elder brother of Gotabaya Rajapaksa.
He was reacting to the concerns expressed by political parties in Tamil Nadu on the election of Gotabaya Rajapaksa.
Some political parties in Tamil Nadu have expressed concern at Gotabaya Rajapaksa's poll victory.
In a tweet, Namal Rajapaksa urged the Tamil Nadu parties to stop criticising the elected President of Sri Lanka and think about the welfare of Tamils in the island nation.
He also said that political leaders in Tamil Nadu never thought deeply about the welfare of the Lankan Tamils, but used the latter as their political dice.
Namal Rajapaksa also recalled the visit of MPs belonging to the DMK and the leader of VCK Thol Thirumalavan in 2009 and the friendly discussions they had with then President Mahinda Rajapaksa.
All the political parties in Tamil Nadu have been demanding the trial of Mahinda Rajapaksa for war crimes and human rights violations against Tamils since 2009, when the internal strife ended in the island nation with the defeat of the Liberation Tigers of Tamil Eelam (LTTE).
Reacting to Gotabaya Rajapaksa's electoral victory, DMK President M.K. Stalin said that Tamils all over the world, including those in Sri Lanka, were disappointed.
Stalin said the United Nations and the world knows about Gotabaya Rajapaksa's animosity towards the Tamils.
The DMK leader also urged Gotabaya Rajapaksa to shed his enmity towards Tamils and treat them as citizens with constitutional rights.
MDMK leader Vaiko had termed the election of Gotabaya Rajapaksa as the saddest day for the Tamil race as he was the Defence Secretary when thousands of Tamils were killed in 2009.
On his part, PMK Founder S. Ramadoss said that after the election of Gotabaya Rajapaksa, a separate Tamil Eelam is the only solution for the safety and welfare of Tamils in Sri Lanka.
Ramadoss said Tamils who are treated as second class citizens in Sri Lanka would now be treated as fourth grade citizens.
( With inputs from IANS )