Northern Territory Police have arrested a man after an aggravated burglary in Millner earlier this morning.

At 4:25am, police received reports that an unknown man had unlawfully entered a residence on Trower Road.

The man has allegedly assaulted a 23-year-old male resident, causing significant injuries to the victim before fleeing the scene.

The victim was conveyed to Royal Darwin Hospital and remains in a critical condition.

Casuarina general duties arrested a 29-year-old man in a vehicle in the area a short time later.

He remains in custody as investigations continue.

Anyone who witnessed any suspicious behaviour in the surrounding areas, especially if you have CCTV, is urged to contact police on 131 444.