Shopkeeper uses sign to fend off robbers

A shopkeeper has fended off two armed men with a metal-framed sign during a struggle that left a woman injured in Sydney's west.

Police said two men wearing hooded jumpers entered a grocery store in Blacktown about 7.30pm on Friday (AEST).

The men allegedly threatened a female shop attendant with a knife, before she pushed them away and a struggle began.

A male shopkeeper stepped in, hitting the men with a metal-framed sign.

The shopkeeper's jacket was slashed with a knife, but he was not injured, and the men fled on foot empty-handed.

The woman was taken to hospital with minor injuries to her arm and face.

Police have asked anyone with information to come forward.