A man has been arrested over a hit-and-run incident in Melbourne's north-west that left a teenage boy dead and a teenage girl in a critical condition.

A car struck the two 17-year-olds from Kings Park on Taylors Road at Delahey on Tuesday night.

They were both taken to hospital and the boy died on Wednesday, while the girl remains in a critical condition.

Police arrested a 33-year-old Hillside man at his home on Thursday afternoon.

Police alleged the driver hit the pair and did not stop at the scene.

Officers had earlier identified the model of the car from a broken headlight recovered at the scene, and also acquired CCTV footage.

Detective Inspector Bernie Rankin said the arrest sent out a warning to all drivers.

"The message out of all of this is people who are involved in a hit-run crash who leave the scene, and particularly in a case where someone is hurt, with modern technology, with all those things out there that assist enforcement and people helping us out with information, eventually you will be tracked down," he said.

"And you'll face the consequences of leaving someone on the road."

Detective Inspector Rankin said police had seized a vehicle that matched the description of the car involved, and another person was helping them with their inquiries.