A 16-year-old girl was sexually assaulted by an armed bandit in a brazen daylight attack at a suburban supermarket yesterday.

Police believe the attack happened after the teen entered a toiled block at the rear of the Brighton supermarket about 12pm.

It is believed the girl's attacker followed her into the Gatehouse St toilet block and threatened her with a syringe before sexually assaulting her.

The man is described to be 170cm tall and wearing a black balaclava, black hooded windcheater and black trousers.

The man spoke with an Australian accent and had dark eyebrows and hazel green eyes.

Vile sex attack on teen while shopping in Brighton | Herald Sun