A GIRL'S pleas for help were ignored as she was being sexually assaulted by two men in a Sydney shopping mall, police said yesterday.

The 15-year-old was dragged into a garden bed by two men as she walked through Parramatta Mall at Church St about 2am on Sunday.

She told police she cried out for help to a nearby male but he apparently ignored her and kept walking.

After being released, the girl went to a fast food restaurant in the mall and told her friends what had happened.

They contacted police and a crime scene was set up.

Police said the men they want to question are both of black African appearance and are appealing for anyone who can assist the investigation to come forward, particularly the male passer-by.

The news comes a week after a Melbourne mother who chased boys throwing eggs was stabbed to death. It brings into question whether passers-by should intervene when they see something criminal.

Rosa Mercuri was knifed in front of her young daughter just after her Lalor house was pelted with eggs on Sunday night.

A boy, 14, has been charged with her manslaughter.