UPDATE 8.30am: A 47-year-old man has been arrested and taken to hospital.
The siege ended at 7.20am, more than seven hours after the man barricaded himself inside the unit. Channel 7 are reporting the man was taken to Liverpool Hospital, with police remaining at the premises and seizing several items after a search the property.
EARLIER: A major police operation is underway in the Sydney suburb of Ashcroft with reports of an armed man barricaded inside a unit.
A NSW Police spokesman told The Huffington Post Australia the incident started just before midnight on Thursday in the south-west Sydney suburb -- and was still underway but had been controlled and there was no ongoing threat to the public.
At this early stage, the incident is not believed to be related to terrorism however the world is on high alert following devastating terror attacks in Paris last month as well as a shooting in the U.S. state of California yesterday.
The suburb is in lockdown with roads around on Devlin Street closedincluding Elizabeth Drive near Maxwells Avenue while nearby residents have been told to stay in their homes.
Buses are also being diverted from the region as the city gears up for peak hour.
Witness Joel Hogan told The Daily Telegraph saw the gunman, describing him as a skinny man in his 40s or 50s.
“He was standing on the footpath yelling at the cops and the cops were hiding behind their car because he had a gun,” Hogan told The Daily Telegraph.
“They had dogs, cops with vests went up there, they were telling him to put the gun down before anyone gets hurt.
“There were probably around ten cops or more and they were all hiding behind the car. He pretty much just walked up the street and the cops were staying back following him.”
A siege situation is underway in Ashcroft with reports a man is inside a unit - armed with a gun. Residents told to stay inside #Sydney— DeborahClay (@DeborahClay) December 3, 2015
Ashcroft is 35 kilometres south west of Sydney CBD, in the council area of Liverpool.
More to come.