"Such letters and assurances (like the one by Sonia Gandhi) are coming for the past two years. Sonia Gandhi and Prime Minister Manmohan Singh had earlier too written such letters to me promising to pass the Lokpal bill," Mr Hazare told reporters in Patna.
"(Their) intention is not clear ... They have been cheating people time and again ... If they had been honest one or at best two parliamentary sessions would have been sufficient to do it (pass the Lokpal bill)," he said.
Asked if he had any expectation from Congress Vice-president Rahul Gandhi on the bill, he said "Everybody is the same. All of them are cheating the people."
Sonia Gandhi had written a letter to Mr Hazare recently and sent it to his Rale Sidhi village home assuring him that the Lokpal Bill, which he is struggling for, would be passed in the coming budget session of Parliament.
The letter was sent days before Mr Hazare launches his fresh campaign from Patna.
Mr Hazare, who was accompanied by retired army chief V K Singh, said he would launch a nation-wide 'movement for 'changing the system to fulfil the 'dreams of Mahatama Gandhi and Jaiprakash Narayan'.
He is scheduled to launch a country-wide 'Vyawastha Parivartan' (change in system) programme and address a "Jantranta rally" in Patna tomorrow.
Mr Hazare said corruption could end only by bringing in change in the system. "Now change in system is our aim."
The change could be brought by passing the Lokpal Bill, introducing the right to reject candidates in elections and decentralisation of power by handing power to gram sabhas and ward sabhas, he said.
On choosing Patna for the campaign, Mr Hazare said Bihar was a 'pious land' as Gandhiji had launched satyagrah against the British rule from Champaran and JP his 'sampoorna kranti' (total revolution) from here, besides being the land of Gautam Buddha.
However, some of JP's disciples had turned 'greedy'.
"The JP movement ultimately led to satta parivartan (change of power) and not vyawastha parivartan (change of system)," he said adding his aim was change in system.
The anti-corruption activist, who is staying at JP's 'Charkha Samiti' residence here, lamented the prevalence of casteism and the wide gap between the rich and the poor and said his movement would wage a war against them.
He said after launching the 'Vyawastha Parivartan' programme from Patna, he would visit four states in February, whose names he did not divulge.
He would later travel through the country to make the people aware of his movement.
On a question if he was missing the anti-graft activist Arvind Kejriwal, who has parted company with him to launch his Aam Admi Party, Mr Hazare said "There is no difference between us ... Everybody is involved in their own work."
Some old timers who belonged to the JP movement of 1974, including Ram Dheeraj, Rajiv Hemkesav and Rakesh Rafi who would be present in the rally tomorrow, the organisers said.
Retired army chief V K Singh told reporters that blood-stained blades of grass from the place where Mahatma Gandhi was assassinated in 1948 were being brought to Patna to deliver an oath to the people for change of system.
Industrialist and former cabinet minister Kamal Morarka had bought the memorabilia at an auction in London last year.
Sources in India Against Corruption, the organisers of the rally, said that Mr Hazare would be welcomed with some 'Bihar special gifts.'
A 'lota' (small metal pot) filled with soil from Bhitiharwa ashram set up by Mahatama Gandhi during the 1917 Champaran satyagrah, a makhana garland from Mithilanchal, besides a memento depicting Ashok chakra would be there at the rally tomorrow.
Mr Singh said Magsasay awardee 'waterman' Rajinder Singh, social activist P V Rajgopal and journalist Santosh Bhartia would be present in the rally.
Motorcycle rallies were organised in Patna today to mobilise people for the rally to be held at the historic Gandhi Maidan.