Police are investigating the link between two overnight armed robberies at Lutwyche and Wooloowin.

Around 8.15pm a woman entered a Lutwyche Road restaurant and walked behind the service counter where she threatened a female staff member with a knife.

The staff member called for assistance and the chef came out and told the woman to leave. The woman left on foot empty handed and was seen to cross Lutwyche Road into Chalk Street.

The woman was described as Caucasian in appearance, mid 30s with a stocky build, wearing a blue and white coloured striped polo shirt and blue jeans with a white towel wrapped around her head.

Around 8.55pm a woman entered a Lisson Grove convenience store carrying a black coloured back pack while holding a white towel over her face.

The woman approached the female attendant and produced a needle and syringe and demanded money.

The woman fled on foot with a sum of cash and was last seen heading towards Hudson Road.

The description of the woman was similar to that of the earlier incident. She was further described as having shoulder length brown hair.

No one was injured in either incident.