Man assaulted at gunpoint in Sydney's east

An 18-year-old man has been assaulted at gunpoint by a man who demanded he hand over his wallet in Sydney's east.

Police say the teenager was on Strachan Street in Kingsford at about 7.15pm on Wednesday when he was approached by a man who threatened him with a firearm.

The armed man demanded his wallet and pushed him to the ground but when the 18-year-old yelled for help his attacker fled empty-handed.

The teenager sustained minor injuries and did not require medical treatment.

The offender is described as being about 30 years of age, around 180cm tall, with a round-shaped face, short hair and of a muscular build.

He was last seen wearing a grey hooded-jumper and jeans.

Police are urging anyone with information on the incident to call Crime Stoppers on 1800 333 000.