"For too long the nation has tolerated the Congress mentality of subterfuge and secrecy," he said in a statement.
Swamy praised the Trinamool chief for disclosing the Congress preferences after yesterday's meeting with Sonia Gandhi.
"Ms (Mamata) Banerjee has done justice by revealing the sneaky name peddling by Sonia Gandhi to humiliate Pranab Mukherjee. Now the cat is out of the bag for which nation thanks Mamataji," he said.
The Janata Party chief said it was ridiculous for "discredited Congress leaders to try and decry Banerjee disclosing the names of possible Congress nominees."
Lauding the mercurial leader, Swamy said Banerjee has earned her political spurs by uprooting the Communists from West Bengal which Congress could not do. Instead they won seats with her help.
"Instead of showing gratitude and reverence, they now want to belittle her," Swamy said.