The Trinamool Congress on Friday said the BJP is being run by "hired people" and that there is no alternative to Chief Minister Mamata Banerjee in West Bengal.
Senior TMC leader and Education Minister Partha Chatterjee also said the BJP has become a place for people who have not been able to show loyalty to the party.
"BJP is being run by hired people... Trinamool Congress is a big banyan tree. If two or three leaves fall, nothing happens to the tree," he told reporters here.
"TMC workers are with Mamata Banerjee. There is no alternative to her in the state," he added.
Mr Chatterjee said the TMC has gained from strength to strength under Ms Banerjee's leadership, and the party has an ideal mix of the old and the young.
Asked about the resignation of Forest Minister Rajib Banerjee from the state cabinet, he said, "I have nothing to say. Why they come and why they leave I don't know. They enjoy power during their tenure and leave only at the time of elections."
Mr Banerjee is the third Bengal minister after Suvendu Adhikari and Laxmi Ratan Shukla to resign in the last few weeks.
"Those who are leaving the TMC will realise their mistake someday," Mr Chatterjee said.
Meanwhile, actor Sourav Das and BJP candidate for the 2016 Kalna assembly seat, Newton Majumdar, joined the TMC earlier in the day.
Mr Chatterjee also said the state government's "Duare Sarkar" initiative will be extended till February 8.