Richmond Police are asking for your help in locating a missing 14 year old Sydney girl could be in Lismore or Goonellabah.

Crystal Walker has been missing since 9am on Thursday March 26 at Petersham railway.

She is described as being of Aboriginal/Torres Strait Islander appearance, about 175cm tall, of thin build, with long dark curly hair.

Crystal has orthodontic braces and was last seen wearing a grey long sleeve jumper and black leggings.

It is believed Crystal may be frequenting Lismore or Goonellabah.

Anyone with information or who may have seen Crystal are urged to contact Marrickville Police Station on (02) 9568 9299 or Crime Stoppers on 1800 333 000.