A group of women doing Tai Chi in a park at sunrise are believed to have discovered a man with fatal stab wounds outside Hurstville train station on Saturday morning.
The stabbing victim, believed to be aged in his 50s, staggered at least 20 metres before collapsing at the Forest Road entrance to the station just after 6am.
Police and paramedics rushed to the scene but could not save the man, who suffered "major trauma" and severe lacerations to his body, police said.
A short time after the man's body was found, a man was arrested at a nearby house, and he is being questioned over the man's death.
Inspector David Ralph, from the St George local area command, said a group of women were doing Tai Chi in the park at the entrance to the station where the man's body was found.
Those women are believed to have raised the alarm, and were due to make a formal statement to police on Saturday.
A bloodied white sheet covered what is believed to be the man's body at the entrance to the train station early on Saturday.
Inspector Ralph said soon after police arrived at the railway station, they received further information "that another male possibly involved was at a home close by".
Police went to that house and arrested a man, believed to be aged in his 20s.
Officers also seized a knife that was believed to have been used in the stabbing.
The man has been taken to Kogarah Police Station, where he is assisting with inquiries. No charges have been laid.
Inspector Ralph said it was not clear whether the men knew each other.
A motive for the incident was also unclear.
"We don't know if it was a robbery, we're not sure of the motive, that's something were looking at," he said.
The Forest Road entrance to the train station has been taped off, but trains are still operating through the station. Police have also set up a crime scene at the house where the man was arrested.
Forensic police on scene have placed markers on a grass area just outside the station, and a reusable shopping bag could be seen lying at the scene.
The area where the man was stabbed is located along a busy shopping strip, and not far from Westfield Hurstville shopping centre.
Police were asking businesses along Forest Road if they had CCTV footage of the stabbing.
The story Women doing Tai Chi discovered man stabbed to death at Hurstville train station was published in The Sydney Morning Herald.
The body of a man, who had been stabbed to death, was found just after 6am on Saturday near the Forest Road entrance to Hurstville station.
A short time later, police arrested a man nearby, and seized “an edged weapon”.
He was taken to Kogarah Police Station for questioning.
Members of the public located the body near the station entrance.
”The man had suffered severe lacerations,” a police spokesman said.
“Emergency services were contacted and police from St George Local Area Command attended and established a crime scene.”
7 News said the man who was being questioned was in his 20s and was located in a home not far from the murder scene.