A BJP leader in West Bengal claimed that the total membership has increased from three lakh in 2011 to more than seven lakh in 2013.
Two lakh new members have enrolled in the last six months, which party leaders have attributed to Modi's anointment as the prime ministerial candidate.
The ABVP, youth wing of the BJP, too witnessed a surge in its membership with the enrolment of 45,000 new activists in the last one year, BJP spokesperson and co-in-charge of the party's Bengal unit Siddhinath Singh told a news agency.
He further claimed that the BJP's minority and women's wings too witnessed a 50 per cent jump in membership.
Singh said, "Two factors are responsible for the expanding BJP membership in West Bengal: Declaration of Modi as PM candidate by the party and the lack of an opposition worth the name in the state."
The senior BJP leader noted that such enthusiasm had previously been witnessed on two occasions. First, during the Ram Mandir agitation in the early 90s and during Atal Bihari Vajpayee's rule at the Centre.
Modi will hold rally in Kolkata on February 5.
"The charisma of Modi working in the entire country is also having its impact in Bengal and we will prove it during Modi's rally in Kolkata on February 5," Singh asserted.
The BJP and the RSS have traditionally never been able to make much of an impact in West Bengal, though the party's former avatar Jan Sangh was co-founded by the son of the soil, Shyama Prasad Mukherjee.
The 27 per cent Muslim community in the state, which wields a considerable influence in at least 140 Assembly constituencies out of 294, plays a key role in the power sweepstake, courted aggresively by all frontline political parties.
With a real Opposition missing in West Bengal after the fall of the mighty Left in 2011, the BJP has been slowly working to make its presence felt, especially in the rural areas of south Bengal taking help of Modi's rising graph.
This was reflected in the 2012 Lok Sabha by-poll in Jangipur in Murshidabad district where the BJP candidate polled an impressive 85,867 votes, nearly 10 per cent of the total votes cast representing an eight per-cent rise over votes polled in 2009.
While President Pranab Mukherjee's son Abhijit won by a paper-thin margin of 2,500 votes in the by-poll, the BJP candidate stood third.
This was significant considering the constant 3-6 per cent votes it had bagged over the last two decades, except in 1991-92 when the vote share of the BJP dramatically rose to nearly 16 per cent riding piggyback on the Ram Mandir issue.
BJP state president Rahul Sinha said, "The vote share of the BJP decreased after it allied with the Trinamool Congress in 1998-99. But after the Left parties suffered a rout in the 2011 Assembly election, voters are looking for a new Opposition which can checkmate the Trinamool Congress."
The panchayat and the municipal polls in 2013 are also marked by a rise in the BJP's vote share and narrowing down of the margins of loss of BJP candidates.
A breakthrough was the defeat of Left candidate and Mayor Mamata Jaiswal at the hands of BJP's Gita Rai in the municipal polls in Howrah.
The popularity of the BJP can also be sensed from near about 425 applicants from various strata of society who have expressed their desire to contest as BJP candidates in 42 Lok Sabha seats in the coming Lok Sabha polls.
BJP's ideological twin RSS too has been making steady inroads in south and north Bengal with the grievances and alleged minority appeasement policies of the ruling party playing a role.
He cited the instance of grant of allowance to 30,000 imams of the state, which has been termed by the Calcutta High Court as unconstitutional.
The expansion of the RSS was first noticed by a three-day youth workshop of the organisation in the state last year after a gap of 20 years under the leadership of its chief Mohan Bhagwat, followed by an increase in the number of shakas/branches in every part of the state.