Police are appealing for public assistance following two robberies in Newcastle at the weekend.

About 2.15pm on Saturday, a 23-year-old man was seated in a park on Lexington Parade, Kotara, when he was approached by three unknown men.

The group demanded the man’s phone, wallet and backpack before he was punched in the face.

The group then left the scene before one of the men approached a 15-year-old boy on Park Avenue and threatened him with a knife.

He demanded his phone before fleeing with the remainder of the group.

Both incidents were reported to police a short time later and officers from Newcastle City Police District commenced an investigation.

As police continue their inquiries, officers are urging anyone who may have seen or heard anything in the Kotara area between 2pm and 2.45pm or who may have mobile phone or dashcam footage to contact Newcastle Police or Crime Stoppers on 1800 333 000.