Here are the latest developments:
The focus of discussions among the BJP top brass and the RSS appeared to be on the positions that could be offered to party seniors. Mr Advani, who was the BJP's prime ministerial candidate, is keen on the Speaker's post in which he doesn't have to directly report to PM, sources said.
Consultations also took place at the Rashtriya Swayamsevak Sangh office in Delhi where senior BJP leaders Sushma Swaraj, Kalraj Mishra and Gopinath Munde met the RSS' second-in-command Bhaiyyaji Joshi.
Former BJP president Venkaiah Naidu too visited the RSS' Delhi office and emphatically denied that the Sangh will have any role to play in deciding on members of the cabinet. "It is a routine meeting... don't know why there is so much of talk about it," he said.
Mr Modi, who is staying in Delhi overnight, drove to Mr Advani's residence just a little after noon in the first formal meeting between the two after the party's resounding victory in the elections. The meeting lasted 40 minutes.
BJP president Rajnath Singh, meanwhile, met senior BJP leader Arun Jaitley and organisational secretary Ram Lal as the party discussed government formation. Mr Modi's close aide Amit Shah was also present in the meeting.
In other series of meetings, Lok Janshakti Party chief Ram Vilas Paswan visited Mr Modi along with his wife and son Chirag. At Gujarat Bhavan, Mr Modi was also visited by senior BJP leader Ananth Kumar, who had met Mr Advani earlier this morning. Rajasthan chief minister Vasundhara Raje and Nagaland chief minister Neiphiu Rio also met him. (Read More)
BS Yeddyurappa, the controversial former Karnataka chief minister who rejoined the BJP just before the elections and has won from Shimoga, also met Mr Modi.
BJP general secretary Dharmendra Pradhan who has charge of Bihar, too met Mr Modi. This meeting has significance in view of the political developments in the state, where chief minister Nitish Kumar resigned yesterday owning "moral responsibility" for his party's rout in the general elections.
Mr Kumar is widely seen as having been punished by voters for splitting with the BJP last year, citing the elevation in the party of Mr Modi, his arch political rival. His Janata Dal (United) has won only two of Bihar's 40 seats. The BJP has won 31.
On Tuesday the 282 new BJP members of Parliament will elect Mr Modi their leader and he will be sworn in as Prime Minister on a date to be decided. The invitation list for that ceremony runs to about 3000, sources have said. (Also Read: Narendra Modi Assures Jayalalithaa of 'Absolute Cooperation' Between Centre, Tamil Nadu)