Geelong Crime Investigation Unit detectives are investigating after a Highton supermarket was robbed at gunpoint yesterday afternoon.

A man entered the grocery store, located at the corner of Colac and South Valley roads about 4pm.

He has approach a staff member at a cash register, produced a firearm from a green eco bag and demanded cash.

The man has then taken an amount of money and fled.

He was last seen driving in a northerly direction along Colac Road in a red Holden Commodore.

The offender is believed to be aged in his late-20s or early-30s, with a fair complexion, pitted skin, long, brown, wavy hair and appeared to be missing most of his teeth.

He was wearing a blue beanie and dark blue jacket.