A man has died after a fatal crash on the Roper Highway last night. 

The 36-year-old pedestrian was struck by a 4WD vehicle travelling west on the highway. 

The driver stopped to assist and conveyed the man, and a relative, to Mataranka Clinic where he was declared deceased at 8.10pm.

Local police have secured a crime scene on the Roper Highway. Detectives from Major Crash Investigation Unit travelled to the location this morning to inspect the seized vehicle, the crime scene and to investigate the circumstances surrounding the incident.

The driver returned a negative result for alcohol and has undergone a blood test for drugs.  He continues to assist police with enquiries.

Detective Senior Sergeant Brendan Lindner has issued a plea for motorists and pedestrians to take care on the roads.

"Tragically, we are seeing a repeat of 2019, in terms of fatalities in December. Christmas is a time for families to get together and should not be a time to mourn the loss of a loved one. Please take great care on the road."

Anyone with any information about the crash is urged to contact police on 131 444 and quote reference number 9507663.