A mysterious liquid hurled in a shocking street attack has left a woman hospitalised with a chemical burn.

The 27-year-old was at the intersection of Norfolk Rd and Callistemon Cl in northwest Sydney’s North Epping about 6.15pm on Wednesday when she was approached by a woman she didn’t know.

Without warning, the stranger allegedly splashed her with a cup of unknown liquid, hitting her face, clothes and headphones.

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The victim immediately called police and was rushed to Ryde Hospital, where she was treated for a chemical burn.

Police searched the nearby area for the attacker but came up empty, and have now appealed to the public for help identifying the woman.

She is described as being of Asian appearance, wearing a light-coloured cap, an N95 white face mask, a black jumper and dark long pants at the time.

She was holding a silver, metal cup in her hand.

Police are urging anyone with information to come forward as the investigation continues.