Man charged after 'marrying' girl, 12

A man who was arrested for allegedly having a sexual relationship with a 12-year-old girl has told police that he married the child in a religious ceremony in NSW earlier this year, police will allege.

The 26-year-old man will face Burwood Local Court on Friday charged with 25 counts of sexual intercourse with a child between the ages of 10 and 14.

Detectives from the State Crime Command's Child Abuse Squad arrested the man at a home that he shared with the child in Guildford on Thursday.

Police allege that the man met the girl in the Newcastle suburb of Wallsend in 2013 and became involved in an ongoing sexual relationship with her.

The pair then allegedly moved to a house in Guildford, in Sydney's west, where the man continued the relationship with the girl.

"Police will allege that the man and child were 'married' in a religious ceremony in NSW earlier this year," police said in a statement.

Police say the marriage was illegal, but would not elaborate on what religion was said to be involved.

The 26-year-old man, who is from a different cultural background, allegedly told police he did not believe he was committing an offence.

The girl's parents are believed to have known that their daughter was living with the man, and she was not officially reported missing.

The man was taken to Auburn Police Station where he was charged and refused police bail on Thursday.

Investigations by the Child Abuse Squad are continuing.

Police are urging anyone with information about the man's relationship with the girl to call Crime Stoppers on 1800 333 000 or use the Crime Stoppers online reporting page.