Slogans were raised in support of Sharad Pawar and against Ajit Pawar by a group of NCP workers outside YB Chavan Centre on Saturday.
Shiv Sena-Congress-NCP will address the media shortly at the venue.
Earlier in the day, Devendra Fadnavis took oath as Chief Minister of Maharashtra for the second term.
Ajit Pawar took oath as Deputy Chief Minister of Maharashtra.
However, NCP chief Sharad Pawar said that it was the decision of Ajit Pawar to join hands with BJP.
"Ajit Pawar's decision to support the BJP to form the Maharashtra Government is his personal decision and not that of the Nationalist Congress Party (NCP). We place on record that we do not support or endorse this decision of his," he tweeted.
The move came at a time when deliberations between Congress, NCP and Shiv Sena had seemingly reached the final stage on Friday. Earlier, NCP supremo Sharad Pawar had claimed that there was a consensus on Sena chief Uddhav Thackeray as chief minister of the alliance government.
Shiv Sena bagged 56 seats while 44 seats went to Congress in the 288-member Maharashtra Assembly.
The BJP, which emerged as the single largest party, could not stake claim to form a government as its ally Shiv Sena remained firm on rotating the Chief Minister's post and equal sharing of Cabinet berths.
Shiv Sena parted its ways with BJP to explore ways to form a government. It, however, failed to prove the support of the required number of MLAs in the time given by state Governor Bhagat Singh Koshyari.
The Governor had then invited NCP, the third-largest party, to prove its ability to form the government failing which President's Rule was imposed in the state.
( With inputs from ANI )