The Northern Territory Police Force have charged a youth after a serious assault at the Royal Darwin Show overnight.

Around 8:20pm, police received reports that a 15-year-old male had assaulted another 15-year-old male with a knife at the showgrounds after an altercation.

Police and St John Ambulance attended, and the victim was conveyed to Royal Darwin Hospital where he currently remains in a stable condition.

The alleged offender fled the scene, with police arresting him a short time later at a residence in Palmerston.

He has now been charged with Recklessly endanger life and Possess, carry, use a controlled weapon.

The 15-year-old remains in custody awaiting a bail review.

Police are still urging anyone with information to make contact on 131 444 and quote reference P25199834.