Man who allegedly wed 12-year-old in jail

A Lebanese man living in Australia on a student visa will spend his first night in jail after allegedly "marrying" a child bride in a religious ceremony.

Ahmad Cham ma, 26, allegedly met a 12-year-old girl in the Hunter region in 2013 and became involved in an ongoing sexual relationship with her.

The pair then allegedly moved to a house in Sydney's southwest, where they continued the relationship.

Police claim the man and child were married in an Islamic ceremony in NSW earlier this year and the girl is now 13.

He was charged with 25 counts of sexual intercourse with a child between 10 and 14 years.

The sexual assaults took place between January 1 and February 4.

Wearing a striped polo shirt and a black beard, the man made a brief appearance at Burwood Local Court on Friday and spoke via an Arabic interpreter.

The Newcastle University student made no application for bail and it was formally refused.

The court heard he will make a bail application during his next court appearance on February 12 at the same court.

NSW Community Services Minister Pru Goward said the case was brought to the attention of authorities by Centrelink.

Ms Goward said anecdotal evidence suggests forced marriages between children and adults was an ongoing issue among Sydney communities.

"This is a very secretive practice ... but it is not an unknown practice," she said.

"I understand there are actually a significant number of unlawful, unregistered marriages to underaged girls in NSW, particularly in western Sydney, southwest Sydney and the Blue Mountains."

The girl has been taken into state care.