A man who robbed a service station with a knife rode off on a pushbike with a small number of items he stole, NT Police said.

Police director of communications Mark Wilton said in a statement that just after 10pm Wednesday police received reports of an unknown man, armed with a knife, entering a service station on Bagot Rd, Coconut Grove, and threatening a member of staff.

He said the offender allegedly stole a number of small items and fled the scene on a pushbike.

Mr Wilton said that a short time later, police received another report that an unknown man had entered a service station on Bagot Rd, Ludmilla, and again threatened staff with a knife before stealing cash and fleeing the scene.

There was no mention that that offender made his get away on a bike but police said they believe it was the same offender in both incidents.

Police are asking anyone with information or who may have witnessed the crimes to call them on 131 444, or to report what they know to Crime Stoppers anonymously on 1800 333 000 or through.