Addressing an election meeting at Haringhata in Nadia district, Banerjee said she had directed Union Minister and party general secretary Mukul Roy to file the defamation suit.
Deb yesterday accused Banerjee of using black money also for the helicopter expenses during the election campaigning but the Trinamool leader described the allegations as a `canard`.
"Even for drinking a cup of tea in my de partment I pay from my own purse and not the railway funds," Banerjee, who is Railway Minister, said amid loud applause from the large crowd.
Claiming that the helicopter she is using has been given by the Congress, she wondered where the helicopter, used by the CPI-M during the 2004 Lok Sabha polls, 2006 assembly polls and 2009 Lok Sabha polls, was now.
"Pranabda (Union Finance Minister Pranab Mukherjee) has asked me (to use the helicopter). It has come as a great help in reaching many people across the state in a short time in the scorching heat," she said.
Trinamool Congress leader Sudip Bandyopadhyya demanded that the Election Commission take stringent action against Deb.
"Mamata Banerjee is the epitome of honesty and no one in the country will believe such an allegation against her," Bandyopadhyya, the chief whip of the Trinamool Congress parliamentary party in the Lok Sabha, told PTI here.
The Trinamool MP said that all election expenses have to be submitted by candidates to the Election Commission within a stipulated time period as per provisions of the Election Commission.
"A special observer has been deployed who looks after the day-to-day expenditure of every candidate in detail," he said.