A 12-year-old boy and two teenage boys have been charged over an aggravated robbery at a service station in Ludmilla on Sunday, where one of the boys allegedly assaulted a male employee with a screwdriver, causing a minor injury, NT Police has said.

In a statement NT government crime marketing manager Sita Bacher said that about 11pm on Sunday police were told that four youths entered the service station on Bagot Rd and caused damage and threatened employees.

She said one of the youths allegedly assaulted a male employee with a screwdriver, causing a minor cut to his wrist that did not require medical treatment, and then all four ran off.

The 12-year-old, a 13-year-old, and a 15-year-old were all charged with two counts of aggravated robbery, one count of theft, and one count of aggravated assault, Ms Bacher said.

While another 13-year-old boy was referred to the Territory Families, Housing and Communities Department.