In a three-page letter, Hazare said such remarks were part of a "conspiracy" to defame him and ensure that those people who supported him during the April protest did not do so in future.
A "hurt" Hazare said, "I request you to ensure that responsible leaders from your party should not resort to character assassination and mislead people on the Jan Lokpal Bill.
"If the Congress party has any concrete evidence (to prove the allegations), please make it public," he said.
He also said it did not augur well for the country if responsible leaders start "telling lies only to clinch to power" by misleading people on issues.
His letter came in the backdrop of Congress general secretary Janardhan Dwivedi dubbing him as a "mask" of BJP while other leaders attacked the civil society on Lokpal Bill.
"If the responsible leaders in the party and government resort to spreading lies, it is not good for the future of the country. Many senior leaders in your party have said that I am a mask of BJP and RSS. In the 73 years of my life, I have never gone close to any party or front because there is corruption everywhere," he said.
To buttress his point, he said he had criticised the Gujarat government for corruption and asked, "Had I been associated with BJP, I would not have talked about such things".
Hazare had earlier kicked up a controversy by praising Modi for development works in rural Gujarat.