Police are investigating the armed robbery of a pizza delivery driver in Toowoomba yesterday.

Initial information suggests around 5pm, the 18-year-old driver was flagged down by a group of men on her way to a delivery on Alfred Street.

After she handed over the pizzas, one of the men produced a knife and demanded money.

After she complied, the man also took her phone.

The men were last seen running south down Alfred Street.

The woman was not physically injured as a result of the incident.

One of the men is described as being Caucasian in appearance, in his early 20s, and of a proportionate build with short brown or blonde hair.

He was wearing a white hooded jumper, a flat peaked cap, and a pair of black faded ¾ length shorts.