Man charged over NSW girl's train assault

A man has been charged with indecently assaulting a 12-year-old girl on a Sydney train.

Police offered a $1000 reward for information about the man, after a girl was assaulted when she and her mother were about to leave a train as it approached Wolli Creek station on November 4.

Police say the man allegedly reached under the girl's skirt and grabbed her buttocks.

The girl and her mother got off the train and immediately alerted police, who were unable to find him.

Following information from the public, police arrested a 35-year-old man at a shopping centre in Miranda and charged him with indecent assault of a person under 16.

He has been granted conditional bail to face Sutherland Court on February 21.