The family of a 16-year-old Indigenous boy killed after a collision with an unmarked police car in Sydney has called for an independent investigation into his death.

On Saturday morning Jai Wright was thrown from a motorbike after a collision with a police car in Alexandria. He suffered serious head injuries and died in hospital on Sunday afternoon.

Lachlan Wright described his son, a former International Grammar School student who was undertaking an electrical apprenticeship, as a "proud Aboriginal boy" who could "get along with everyone".

"No-one really had a bad thing to say about him... We will never move on without Jai. He will always be with us in our thoughts every day."

Mr Wright said his family deserved to know what happened to their "bright and lively boy" and had been given "inconsistent information by police".

"Any parent wants to know how their little boy has died. That is why we are calling for entirely independent inquiry away from the police," he said outside the Royal Prince Alfred hospital on Monday, Guardian Australia reported.

Mr Wright alleged a senior police officer told him his son was being pursued by police before the unmarked police car turned in front of him, causing him to fall off the trail bike.

He said a police investigator later told him there had been no pursuit and that his son had lost control of the motorbike before running into a parked unmarked police car.

NSW Police said officers saw two suspected stolen vehicles, including the trail bike, around 7am on Saturday in Newtown, and that the bike was last seen turning right into Sydney Park Road in Alexandria before a collision with the unmarked police car at the intersection of Henderson and Mitchell roads in Alexandria at 7.35am.

Mr Wright has called on witnesses or anyone who has CCTV or other footage of the collision to come forward.