"Four years have gone by, but the Lokpal has not come. The public is asking only one question, till when will you blow the tune of falsehood?
"Are the 'defenders of democracy' and 'harbingers of accountability' listening?" he asked in tweets using '#FindingLokpal' as hashtag.
Under the Lokpal and Lokayuktas Act, 2013, ombudsmen are to be appointed at the Centre and in states for inquiring into allegations of corruption against public functionaries.
PM Modi had then tweeted, "Am very proud of the positive and proactive role played by BJP MPs under leadership of Sushma Swaraj and Arun Jaitley in passing Lokpal Bill."
The Lokpal Bill was passed by Parliament in 2013, but the appointment of the anti-corruption ombudsman is stuck in procedural wranglings for the last four years.