A crime scene has been established at a fast food store in Merrylands following an armed robbery early this morning.

About 2.45am (Tuesday 23 October 2018), a man entered the Pitt Street store armed with a knife. He approached the counter and threatened a male staff member while demanding cash from the register.

The employee complied and the armed man took the money before running from the store.

Officers from Cumberland Police Area Command arrived on scene and have commenced inquiries.

The man has been described as Caucasian in appearance, about 175cm tall with a medium to thin build and wearing a blue and black coloured hooded jacket and black shorts with a white stripe down the side. He was wearing black joggers with white soles.