Mamata Banerjee comments were widely seen as a pointed swipe at Congress leader Rahul Gandhi.
Mamata Banerjee's caustic "what UPA?" comment directed at the Congress after a meeting with Maharashtra leader Sharad Pawar on Wednesday came in a blast of criticism that did not spare Rahul Gandhi.
No one can do politics by staying abroad "half the time", Mamata Banerjee said in an interaction in Mumbai.
"If one does nothing and is abroad half the time, then how will one do politics? For politics there should be continuous endeavour," the Bengal Chief Minister said in an interaction with members of the civil society.
The comments were widely seen as a pointed swipe at Congress leader Rahul Gandhi, who recently vacationed abroad.
"India's Constitution, its democratic system is such that mere opposition unity will not help. Why am I travelling so much? Who wants to leave Bengal and go around everywhere? I do that so that others also do the same and there is a competition. I want the federal structure to be strong. If all regional parties are together, it is very easy game to defeat the BJP," Ms Banerjee said, to applause from the audience.
On whether she could lead the opposition alliance against the BJP, she said she was a "small worker" and preferred to stay so.
Later, to a question from the media on her meeting with Sharad Pawar and whether she believed the Nationalist Congress Party (NCP) leader should lead the UPA (United Progressive Alliance), Ms Banerjee snubbed the Congress again.
"What UPA? There is no UPA now? What is the UPA? We will clear all issues. We want a strong alternative," she said.
The Trinamool Congress chief is on a three-day visit to Mumbai to meet leaders of the Shiv Sena and NCP - both Congress allies -- amid a widening rift with the Congress.
Congress leaders have reacted sharply to Ms Banerjee's comments.
"Mamata Banerjee is absolutely wrong that the UPA does not exist. It is also wrong to launch personal attacks on Rahul Gandhi. Mamata Banerjee''s allegation that Rahul ji is not visible anywhere is wrong. Congress is raising every issue and is fighting everywhere. Our aim is to defeat BJP but some people are helping that party only. Congress is in power in many states and also in Opposition in some places," said Congress leader Mallikarjun Kharge today.
"UPA. Without the Congress, UPA will be a body without a soul. Time to show opposition unity," Congress leader Kapil Sibal tweeted this morning.