The Northern Territory Police Force has arrested a 26-year-old male after he tested positive for an illicit drug following a car crash near Humpty Doo yesterday.

Around 8:25pm, the Joint Emergency Services Communication Centre received a report of a crash involving a car and an e-bike on Challoner Circuit near Lloyd Road.

A vehicle driven by a 26-year-old male was travelling in the opposite direction of a 15-year-old male travelling towards Freds Pass Road on an e-bike when it allegedly made a right-hand turn into the path of the e-bike.

The rider, who was allegedly not wearing a helmet, was conveyed to Royal Darwin Hospital with serious head injuries where he remains in a critical but stable condition.

The 26-year-old male tested positive for illicit drugs in a roadside test and was arrested for a drug analysis which revealed the presence of methamphetamine in his body.

Territory Road Policing are continuing to investigate the incident.

Anyone with information or relevant dash cam footage is urged to make contact on 131 444.

Anonymous reports can be made through Crime Stoppers on 1800 333 000 or via Crime Stoppers Northern Territory | Make a Report.