Two teens rob woman in southwest Sydney

A 19-year-old woman has been pushed to the ground and dragged along a footpath during a robbery by two teenage boys in Sydney's southwest.

Police say the woman got off a train at Belmore station at about 8pm on Monday and was approached by the boys as she walked along Burwood Road.

One attempted to grab her bag from her shoulder and as she fought back she was pushed to the ground and dragged along.

A passing motorist stopped to assist her and as he approached one of the boys grabbed the woman's iPhone before the two teens ran off.