Police have described the scene where a 51-year-old woman was found dead in her home at Numbaa as "very confronting".
Nowra Crime Manager, Detective Inspector Scott Nelson would not reveal how the woman died or for how long she had been dead before being discovered.
Emergency services were called to the home on Comerong Island Road shortly before 11.30 am on Friday where they found the woman inside.
"She sustained fatal injuries," Det Insp Nelson said "the scene was very confronting for first responders."
A crime scene was established and forensic officers remain at the location examining the home.
Det Insp Nelson said shortly after midday a 37-year-old male "was arrested nearby" and "remains at Nowra Police Station and is assisting with inquiries".
Det Insp Nelson said it is "believed the man and the dead woman might have been known to each other".
"That is a line of inquiry police are pursuing," he said.
"We don't believe this is domestic related."
He said the man in custody is "known to police".
Det Insp Nelson reassured the public that they didn't have to fear "someone was on the loose".
"We can't say if it was a targeted attack but we do believe it's not a random attack," he said.
It is understood the family became concerned on Friday morning when they could not contact the woman, with her son then finding her body in the home.
The house and an adjacent property have been cordoned off and Det Insp Nelson said all areas are considered to be part of the crime scene.
"It's a significant area in size and forensic teams will be there for a number of hours," he said.
"Forensic police remain at the scene and they will determine the cause.
"The investigation is in the very early stages and we have specialist forensic resources coming from Sydney and the homicide squad will also be assisting with inquiries."
Det Insp Nelson would not say if a weapon was used in the incident.
"I can't go into details of the woman's injuries but it was quite confronting for first responders," he said.
"At this stage we can't rule anything in or out. We are still talking to a number of witnesses at this stage as to who found what."
He would not comment if there were signs of a struggle or if the incident was drug related.
It is understood the woman lived alone and police will look into her movements and who she may have come into contact with in the past 24 hours.
"It's too early to say, the forensic services are at the crime scene, they are the experts and professionals - we'll have a full forensic debrief to their investigation later tonight."
Police have appealed to anyone who might have driven along Comerong Island Road between Nowra and Comerong Island in the past 24 hours and might have dashcam footage to please come forward.
"It is a semi-rural location, it's not like your typical urban environment with a lot of neighbours or foot traffic," he said.
"We are knocking on doors and neighbours are assisting us.
"People who drive this road know the area and if they have any dashcam footage they can contact Nowra Police on 44219699 or Crime Stoppers on 1800 333 000."