Brian Lee, 29, has been charged with murder following the fatal stabbing of 56-year-old Klaus Petr near Hurstville train station in the early hours of Saturday morning.
Police were called to the Forest Road entrance of Hurstville station in Sydney's south just after 6am, following reports that a man had been stabbed.
Mr Petr staggered at least 20 metres before collapsing, and was discovered by a group of women doing Tai Chi in a park, police said.
He suffered "major trauma" and severe lacerations to his body and could not be saved by police and paramedics who rushed to the scene.
Shortly after Mr Petr's body was found, Mr Lee was arrested at a nearby house and taken to Kogarah Police Station, where he was assisting with inquiries on Saturday evening.
Officers also seized a knife that was believed to have been used in the stabbing.
Mr Lee was due to appear at Parramatta Local Court on Sunday, but was not required to appear and is due back in court at Burwood in mid-March.
A NSW police spokesman said on Sunday that the attack appeared to be "random".
Mr Lee was arrested following a tip-off from the public.
Inspector David Ralph, from the St George local area command, said on Saturday that it was not clear how the men knew each other, or what the motive for the incident was.
"We don't know if it was a robbery, we're not sure of the motive, that's something were looking at," he said.
Mr Petr's wife, Ann, described him as a kind and quiet person.
"I never think [sic] anything like this [would] happen at all," she told Seven News on Sunday.
"He's a very good person. I just feel shocked."
The area where the man was found is located along a busy shopping strip, and not far from Westfield Hurstville shopping centre.
with AAP, William McInnes, Kate Aubusson