An intruder remains on the run after allegedly forcing their way on to a Royal Australian Air Force base in Darwin, assaulting a member of the defence forces and fleeing in a stolen car.

Defence confirmed in a statement that on Monday afternoon a person “unlawfully gained access” to the base in the suburb of Winnellie.

“RAAF Darwin security, the Joint Military Police Unit, Northern Territory Police and Australian Federal Police responded, and base lockdown procedures and protocols were implemented,” defence said.

“The individual allegedly assaulted a Defence Force member and proceeded to leave the base in a stolen vehicle.”

The NT police, who are leading the investigation, confirmed it responded to the incident about 4.30pm on Monday.

The person was last seen travelling in the stolen car about 15km from the base.

“The vehicle was later sighted travelling south on the Stuart Highway and a pursuit commenced, but was called off near Palmerston after police lost sight of the vehicle,” police said in a statement.

“Investigations are continuing.”

Police said the offender was yet to be identified, but the stolen vehicle was a white Ford Ranger.