Northern Territory Police are investigating a rollover on the Douglas-Daly Research Station, in which a 26-year-old man has died.

The single-vehicle crash happened this morning. It is understood that the victim was a private subcontractor on the property and not an employee of the Department of Primary Industry and Fisheries.

DPIF has arranged counselling for staff.

As the fatality happened on a property and not on the NT road network, it is not counted in the road toll, which remains at 18.