The balaclava-clad man smashed open a display cabinet and stole an unknown amount of jewellery from the store in the Werribee shopping centre at about 5pm on Tuesday.

However, during the course of the heist, a female customer confronted the thief and prised away one of the hammers before throwing it in his direction as he ran away.

The customer and other staff were uninjured in the incident, police confirmed on Wednesday.

The offender was last spotted entering a dark grey-coloured sedan parked outside the precinct and the car took off along Heaths Road.

Police released an image of the man, dressed in a balaclava, dark grey hoodie and black tracksuit pants, as they appeal for witnesses to come forward.

Australian Associated Press