Addressing a public rally here, the Trinamool Congress chief made the charge following Modi's refusal to roll back his decision to demonetise the old 500 and 1,000 rupee notes.
She added that the demonetisation had led to a nationwide cash crunch and resulted in an "emergency like situation".
"Now the Samajwadi Party and Trinamool are one," she told the rally, also attended by several Samajwadi Party leaders.
"Uttar Pradesh has led the country in every fight. Jawaharlal Nehru and other leaders who emerged after him are from this state," she said, explaining her decision to travel to the state.
Banerjee vowed to hold mass protests against demonetisation in other parts of the country as well.
She earlier addressed two rallies in Delhi including one with AAP leader and Delhi Chief Minister Arvind Kejriwal.
Although Chief Minister Akhilesh Yadav did not attend the rally, he received Mamata Banerjee when she flew into Lucknow on Monday evening.
A large number of Samajwadi Party workers at the rally began to leave when they came to know that Akhilesh Yadav would not come.