A Sydney mother has described how she was subjected to a vicious attack outside a busy suburban shopping centre, with a woman repeatedly shouting "you're so ugly" at her and demanding she remove her niqab.

The former child care worker and swim instructor, who has asked not to be named, said the woman yelled at her: "you should take that off", "I don't know what you look like", "you're not Australian" and "F*** off back to Lebanon".

The Sydney mother-of-four said she had been subject to racial abuse in the past.

The mother-of-four, 36, from Auburn, had just left Bankstown Central Shopping Centre on Friday afternoon when she noticed a woman staring at her, shaking her head and muttering.

"First thing she said to me was "take it off"," the woman said. "She was demanding that I take it off and because I wouldn't take it off that's when she lost it."