About 8.30am, an 18-year-old man was approached by a group of males while at a bus stop on Whitford Road.

Police were told one of the men threatened the 18-year-old with a knife and demanded he hand over his mobile phone. The man received a small cut on his hand as he gave the man his phone.

The group fled and police were notified.

Green Valley police spoke to the man and conducted a canvass of the surrounding area.

Police are appealing for anyone who witnessed the incident, or any suspicious behaviour in the vicinity of Whitford Road, to come forward.

The armed man is described as being of Caucasian appearance, aged in his early 20s, about 170cm tall, and of medium build. He was wearing a white hooded jumper.

Anyone with information should contact Green Valley police or Crime Stoppers on 1800 333 000.