A day after jubilant parties, street parades and religious ceremonies were held around the country to celebrate the BJP's landslide election victory, Modi was behind closed doors working to form his cabinet.
"All kinds of people are meeting Modi," senior BJP leader Prakash Javadekar told AFP, declining to reveal who were frontrunners for the finance, foreign, defence and other key portfolios.
Modi, a former tea boy who has governed his home state of Gujarat for the last 13 years, is expected to take office later this week after securing the strongest mandate of any Indian leader in 30 years.
He and his right-wing BJP trounced the left-leaning Congress, which has ruled India for most of the years since independence in 1947, piling humiliation on the famous Gandhi family that dominates the party.
- Enormous expectations -
Modi faces enormous expectations from tens of millions of voters after pledging to create jobs and increase development to revive the economy, which is growing at the lowest level in a decade.
After his presidential-style campaign dominated the election, Modi reiterated Sunday his pledge to work with his BJP-led National Democratic Alliance coalition to make India a world leader "once again".
"NDA is committed to creating new opportunities to empower the people of India & to make India a Jagat (world) Guru once again," he said on his official Twitter account.
Modi has toned down his Hindu nationalist rhetoric and promised unity amid predictions from opponents that he will alienate the country's 150 million Muslims and other religious minorities once in power.
Modi is tainted by allegations he failed to stop anti-Muslim riots on his watch in Gujarat that killed more than 1,000 people in 2002. He has denied wrongdoing and a court investigation found no case to prosecute.
On Sunday Modi met the party's elder statesman L.K. Advani, with whom he fell out last year, at his Delhi residence to brief him on the latest stage of the negotiations, according to local media.
Modi's most trusted aide Amit Shah, who steered the BJP's thunderous victory in the critical state of Uttar Pradesh, is tipped to become his boss's enforcer with a top post in the Prime Minister's Office.
Successful lawyer Arun Jaitley, a member of the upper house, has been widely tipped to become finance minister. BJP president Rajnath Singh, a past federal government minister, could also be tapped for a key ministry.
Sushma Swaraj, who led the opposition in the lower house in recent years and is the BJP's most senior woman leader, is also expected to receive a key cabinet position, although she is not close to Modi.Top BJP leaders were also meeting in Delhi with the right-wing Rashtriya Swayamsevak Sangh (RSS), the Hindu nationalist organisation seen as the ideological fountainhead of the BJP.
A senior BJP leader denied they would be taking orders from the RSS on who should be appointed to the new cabinet.
"We come to the RSS headquarters and meet seniors, it is part of our life," M. Venkaiah Naidu told reporters as he arrived there.
The BJP secured 282 seats in the 543-member parliament, the biggest victory since 1984. Congress was devastated, holding just 44 seats -- a quarter of its tally at the 2009 election.
The defeat raises questions about the future of the Gandhi political dynasty after 43-year-old Rahul, who was leading campaigning nationally for the first time, suffered such a resounding rejection.
Congress is holding a meeting on Monday in Delhi at which the election outcome and the party's future direction are expected to be discussed. Local media have speculated that Rahul and his mother, party president Sonia, will offer to resign.