DMK chief M Karunanidhi has appealed for the death penalty to be abolished. Earlier this month, Afzal Guru from Kashmir was hanged for his role in 2001's deadly attack on Parliament. In November, Pakistani terrorist Ajmal Kasab was executed for the 26/11 strikes in Mumbai in which 166 people were killed.
The hangings have provoked criticism from human rights groups.
Mr Karunanidhi's party is a senior member of the Prime Minister's ruling coalition.
His request comes as four men from Karnataka have appealed against the death sentence. The Supreme Court will hear their case on Wednesday. The men, all members of the gang led by notorious sandalwood smuggler Veerappan, were convicted for the deaths of 22 policemen in 1993.
In a letter to party workers, Mr Karunanidhi said the Centre and legal experts should look at "removing hanging from law books in the interest of human rights and humanity."
"Had this opinion (of abolition of death penalty), which is being stressed for a long time given due consideration, death penalties which are continuously being implemented now could have been prevented," he said.
The mercy petition of Veerappan's associates was rejected by President Pranab Mukherjee last week, nine years after they asked for their sentence to be commuted. Their lawyers argue that the "inordinate delay" merits a removal of the death penalty.
The same argument was made by another three death row prisoners from Tamil Nadu, who have been convicted for their role in the assassination of former Prime Minister Rajiv Gandhi. Their case is also being heard by the Supreme Court. Last year, the Tamil Nadu assembly unanimously passed a resolution, urging the President to review their death sentence.