The accused, identified as Srikant S Sarkar, is the survivor's paternal uncle and a resident of Subhash colony in Ulhasnagar township in Thane district.
Quoting from the complaint by the girl's mother, the police said that on January 20, the girl was alone at home, when the accused alleged assaulted her sexually.
"After the incident took place, she narrated the incident and facts to her parents, but since the accused was a close relative, family members had a meeting and sorted out the matter.
Further investigation is on, senior police inspector A S Rane of the Vishnunagar police station said.
The Vishnunagar police has registered an offence under Section 354 (A) and Section 377 of the Indian Penal Code and under Section 4 and Section 8 of the Protection of Children from Sexual Offences Act, 2012, the police said.