One man is dead and three other people have been seriously injured after falling from balconies and roofs in separate accidents in NSW in just one day, police say.

In the most serious incident, a 20-year-old man died from injuries suffered when he fell from the eighth floor balcony of a building in Waterloo early on Sunday morning.

Police believe the man's death, and other serious incidents at Chippendale, Rozelle and at The Entrance on the central coast on Sunday, were all accidental falls from buildings.

A NSW Police spokesman said officers first were called to Danks Street in Waterloo just before 12.30am on Sunday to reports that a man was lying unconscious on a footpath.

Police arrived to find paramedics attempting to revive the man, however he had suffered massive injuries and died a short time later.

Police from the Redfern Local Area Command set up a crime scene at the building and are investigating his death. Initial investigations suggested the man fell from the eighth floor balcony as a result of "misadventure", the police spokesman said.

Just 30 minutes later, at 1am on Sunday, emergency services were called to Warayama Place in Rozelle to reports that another person had been seriously injured in a fall.

They arrived to find a 36-year-old woman with a fractured hip. Police said the woman was trying to gain access to an apartment from the balcony when she fell about six metres to the ground.

The woman had surgery on Sunday, and police said there would be no further police action in the case.

Just before 2am, police then were called to Myrtle Street in Chippendale after a man fell up to 15 metres from the roof of a building onto the footpath.

Police and paramedics arrived to find the man lying unconscious on the street.

Paramedics treated him at the scene before taking him to Royal Prince Alfred Hospital in a critical condition.

At 6pm on Sunday, emergency services were called to Torrens Avenue at The Entrance where a 28-year-old woman had fallen from the second-storey balcony onto a vacant block of land.

The woman was flown to John Hunter Hospital, where she was in stable condition on Monday morning. Police said the extent of her injuries was not known.

Police said they would investigate whether alcohol was a factor in any of the accidents.