Police have arrested a woman in connection with the murder of her companion in Yuen Long during the small hours of Wednesday.

Two others were arrested on suspicion of obstructing arrest and assisting offenders.

Police said they received a report at 4:20am that a man was attacked in a taxi parked on Ma Miu Road.

The 48-year-old man had multiple stab wounds. He was rushed to hospital and was declared dead about an hour later.

Police later arrested a 36-year-old two-way permit holder in Tin Shui Wai, as well as a man and a woman.

“Based on our initial investigation, police believe the 48-year-old male victim was in a relationship with the 36-year-old woman," assistant district commander Tang Yick-kay told a briefing on Wednesday evening.

"Before the incident, the victim and the two arrested women had been socialising near the scene of the crime. When they were about to leave in a taxi, they got into an argument.

"During the argument, someone stabbed the victim with a knife and fled the scene.”

Officers also said they have recovered a knife that they believe was used in the attack.