A man has been arrested after the fatal shooting of an 18-year-old man in the NSW city of Newcastle.

Ekam Sahni died after he was allegedly shot in the chest at the Bar Beach carpark about 11.40pm on Wednesday.

About 11.20am today, a 22-year-old man was arrested at Newcastle Police Station.

Police said their inquiries are continuing.

No charges have yet been laid.

Sahni, a Newcastle local, was allegedly shot after a fight between two groups of people at the beach car park.

After the fight, a white Volvo SUV pulled up, and a man armed with a rifle allegedly jumped out and fired shots, fatally hitting Sahni, before fleeing.

Paramedics treated the teenager, but he died at the scene.

The white Volvo allegedly used in the shooting was allegedly stolen, police said.

It was later discovered burnt out about a 20-minute drive from the car park at Tingira Heights.