Detectives attached to Newcastle City Local Area Command are investigating an armed robbery at Adamstown last night.

At about 10 pm, two victims aged 15 and 13 were walking through the grounds of the Department of Education site on Brunker Road where they were approached by the two male offenders.

Senior Constable Juan Mahoney says one of the offenders was armed with a knife and punched the older victim repeatedly in the face demanding cash.