Police investigating the death of a man, who was dumped outside of North District Hospital with serious injuries early on Saturday, said they had made an arrest.

Detectives said the 32-year-old suspect was picked up in Tin Shui Wai and was believed to be linked to the car used to drop off the victim in Sheung Shui.

Acting senior superintendent Basil Tang, from the New Territories North Crime Regional Headquarters, said officers received a report from a passer-by at around 5.45am on Saturday that the 23-year-old man was lying unconscious near a pedestrian crossing on Po Kin Road, where the hospital is located.

He said the victim was then brought inside the hospital where he was pronounced dead an hour later.

Tang also said that the deceased had multiple injuries that are thought to have been caused by blunt objects, punches and kicks, adding that his cause of death was still under investigation.

Police were called to a suspicious vehicle in Wong Chuk Yuen in Pat Heung on Sunday evening.

"The police arrived at the scene to conduct an investigation and believed that this vehicle was involved in the incident. At the time of the incident, someone put on a fake license plate and abandoned the deceased outside of the mentioned hospital," Tang said.

"The police and laboratory personnel later searched the car and found blood stains and a stun gun."

Police were treating the case as murder, saying they believe others were involved and remained at large.