Union Minister Rajnath Singh, BJP's central observer for election of the legislature party leader, is expected to arrive in Mumbai on Monday and election is likely to take place the next day, a top BJP leader said here in an informal interaction with journalists.
Back channel talks were said to be on between BJP and estranged former ally Shiv Sena for forming a coalition government.
BJP, which has emerged as the single largest party in the 288-member Assembly with 122 seats, has already been offered outside support by 41-member NCP.
With its 63 MLAs, Shiv Sena is the second largest party in the House.
Meanwhile, Rashtriya Samaj Paksha leader Mahadev Jankar, whose party is a pre-poll ally of BJP and has one MLA, said his party is not in favour of any tie-up with NCP.
"We want the new government to come to power without the backing of NCP or Congress against whom BJP fought the poll and highlighted their corruption," Jankar said after meeting state BJP chief Devendra Fadnavis, a frontrunner for chief ministership.
Jankar said his party wanted representation in the new ministry.