Chidambaram claimed that the number of civilians and terrorists killed in Kashmir had almost doubled.
Congress leader P. Chidambaram on Sunday attacked the Modi government's Kashmir policy, saying its "hard, muscular, militaristic" approach had failed to end terrorism in the troubled state.
"It was claimed that the hard, muscular, militaristic approach will put an end to infiltration and militancy. Has it?" the former Home Minister tweeted.
Mr Chidambaram quoted statistics to say that the number of civilians and terrorists killed in Jammu and Kashmir had almost doubled from 28 to 57 and from 110 to 218 from 2014 to 2017 respectively.
The number of security forces killed had also shot up from 47 to 83 in this period.
"If you are one of those who had thought that the hard, muscular, militaristic approach of the government should be given a chance ... you may change your view," Mr Chidambaram said.
The Congress leader said that wisdom lay in actively working towards a political solution to the issues of Jammu and Kashmir, where a separatist campaign raging since 1989 has claimed thousands of lives.
"Both A.B. Vajpayee and Manmohan Singh will be remembered for the diligent efforts to find a solution to the issue."
Separately, another Congress leader and former Central minister, Kapil Sibal, said Prime Minister Narendra Modi's rhetoric over Jammu and Kashmir had come apart.
"Soldiers and policemen martyred almost daily. Will government explain? When will be stop losing lives?" he asked in a tweet.
The twin criticism came a day after a explosion killed four policemen in Sopore in Jammu and Kashmir.