"I don't trust exit poll gossip. The game plan is to manipulate or replace thousands of EVMs through this gossip," Banerjee said in a social media post.
"I appeal to all opposition parties to be united, strong and bold. We will fight this battle together," she said.
Almost all exist polls either gave a majority to the NDA or predicted it would stop close to the magic figure.
The various exit polls also forecast a massive increase in the BJP's number of seats - from two in 2014 to between 16 and 18 in West Bengal.
Banerjee also said, "It is a game plan, planted by the Narendra Modi government. I think it is a total gossip. No one is messenger of god. I do not believe their theory."
She alleged there were 2-3 plans behind such predictions by the exit polls.
"These (exit poll predictions) are plans to weaken opposition parties and these have been circulated so that opposition alliance do not get activated," she said.
Banerjee alleged it was a "conspiracy" to manipulate EVMs.
"Modi during his campaign had said they would get over 300 seats. It is an attempt to establish a lie as a truth through this gossip so that they can replace or manipulate thousands of EVM machines keeping administration in pressure."
According to her, activities of opposition parties would start as they are united and would talk and keep communicating with each other.
"We would decide on the common minimum agenda and also come to a decision what we would propose to the Election Commission and the President," she said.
Banerjee also said the predictions would boost the share market
"These exit polls prediction are absolutely wrong. I have talked to 4-5 opposition leaders and they feel these predictions are fake. I believe in public mandate and I strongly believe that the BJP will lose."