Asserting that BJP is not afraid of anyone, he said those involved in the scam will be arrested and put behind bars.
"You (Mamata) are not protesting against duping of 17 lakh investors in the Saradha scam and coming down on the streets, because your own associates and stooges are involved. We need an answer as to who took away the Saradha scam money.
"We are not afraid of anyone because our workers are not involved in any scam. Whether it's Saradha or anything else, we will do the work of arresting and putting the culprits behind bars," Shah told a rally in central Kolkata.
Asking the Chief Minister to reign in her workers and associates who are alegedly involved in corruption and scam, he said, "If you can't do that then please step down. BJP will provide good governance in Bengal. The countdown has already started and the people of Bengal will show you the way out in the 2016 Assembly polls," he said.
With barely two years left for the Assembly elections, the BJP chief left no one in doubt that he has already started a campaign to oust the Banerjee-led Trinamool Congress government in the state.
"More than 2,000 farmers had lost their land in Nandigram and Singur and you had gone on fast protesting against that injustice. But in this Saradha scam more than 17 lakh people of Bengal have lost their deposits.
"Why don't you (Mamata) feel like sitting on a fast against this scam Why aren't you coming down on the roads for those who lost their savings" Shah asked.
The BJP president's comment comes at a time when the CBI and the ED were tightening their grip in the multi-crore Saradha Ponzi scam probe.
Shah alleged that Bangladeshi infiltration has gone up by five times in the Trinamool regime as Banerjee was only pursuing politics rather than developing the state.
"Bangladeshi infiltration has gone up by five times in the TMC regime. If one Bangladeshi infiltrator comes here, then he takes away the job of a Bengali youth and education of a youth. But Mamata is more interested in politics than development of Bengal. She has to stop infiltration and rising crimes in the state," he said.
Shah, who was in the city to address the BJP's state committee meeting and a rally for the upcoming by-elections to Chowringhee and Basirhat South seats, said both the seats should be won by BJP to raise the voice against injustice and crime against people inside the Assembly.
Accusing the erstwhile Left regime of "ruining Bengal", the BJP president said the much-hyped political change was of no use as both Trinamool and the Left were "cousins".