Mamata on Saturday, Nov 17 announced that her party would move a no-confidence motion on the first day of the Winter session of Parliament on Nov 22 and appealed to all parties, including the Bharatiya Janata Party and the Left, to support the move.
To move a no-confidence motion in the Lok Sabha, a party needs the support of atleast 50 MPs but Banerjee's party has only 18 MPs.
Sources say opposition parties - including the BJP and the Left - however, are unlikely to bail out the government if Trinamool manages to take it to voting stage.
The BJP on Sunday said the Trinamool Congress did not have enough numbers to bring a no-confidence motion to oust the Congress-led central government and that the party was yet to decide whether to support the move.
"What is the use of bringing the motion if it gets defeated. The Trinamool doesn't have the numbers. Their leadership will have to decide how far they can go. All parties need to carefully chalk out the plan," senior Bharatiya Janata Party leader Murli Manohar Joshi said.
"Numbers are important. If the motion gets defeated, then the government will relax for the next six months as you cannot bring another no-confidence motion during that period. We need to plan well," he said.
"Mamataji telephoned Sushma Swaraj (BJP leader) to seek support for the move. We will take a decision on that only after a discussion with our party leaders and the representatives of the National Democratic Alliance (NDA)," Joshi said.
"Trinamool Congress may say one thing now but may finally act differently. We will have to wait and see," CPI(M)'s politburo member Sitaram Yechury said.
The Opposition is assessing the fact that Samajwadi Party and Bahujan Samaj Party can bail out the government.