Anti-corruption activist Arvind Kejriwal on Wednesday accused Nitin Gadkari, the president of the Bharatiya Janata Party (BJP), of being involved in an irrigation scam in his home state of Maharashtra.
Congress-NCP has governed Maharashtra since 1999.
The scam runs into hundreds of millions of rupees, said Kejriwal, surrounded by his team members who were all wearing Gandhi caps.
Later, Gadkari appeared unruffled at a press conference as he refuted the claims made by Kejriwal, saying they are baseless and are meant to defame him.
"This is a conspiracy to defame BJP," Gadkari said. "I am ready for any kind of enquiry".
Kejriwal, who has set up an anti-corruption political party, had last week accused DLF of arranging favourable loans and real estate transactions for Robert Vadra, the son-in-law of Congress party chief Sonia Gandhi.
The claims were detailed in a document posted on the group's website. Both Vadra and DLF have refuted the charges.
A political novice, Kejriwal has been hogging headlines for his corruption allegations against high-profile people, including Law Minister Salman Khurshid.