The dead include eight children. The body of a girl, Afsana Ansari, 15, was found in the debris during the night, police said.
The number of those rescued from the debris has gone up to 23 with three more persons, including two women, having been pulled out during the night, police said.
The 43-year-old Jilani building collapsed on Monday.
Two civic officials have been suspended in connection with the collapse and an offence has been registered against the building owner, an official said.
The building in the powerloom town - which is around 10 km from Thane - had 40 flats and around 150 persons lived there, an official said.
The building, located at Narpoli's Patel Compound near Dhamankar Naka, collapsed while the residents were asleep.
Teams of the National Disaster Response Force (NDRF) and personnel of the Thane Disaster Response Force (TDRF) are still at the spot as the search operation continues, he said.
The building was not in the list of dilapidated structures of the Bhiwandi-Nizampur Municipal Corporation (BNMC), he said.
The BNMC suspended two senior officials in connection with the
Meanwhile, a building resident said most residents of the building were tenants and included autorickshaw drivers, vendors and labourers.
A civic official said the building was served two notices, one in 2019 and another in February, over alleged irregularities, but the residents did not leave as the rent was very low.