New South Wales Police allege a masked man fired a 1941 rifle into a home before taking two people hostage during a siege incident at Windang on the South Coast yesterday.

Windang Road, south of Wollongong, was closed on Sunday after public reports a masked man clad in black carrying two rifles firing several shots.

Following a large-scale police operation, 40-year-old Windang man Simon Fleming was arrested and later and charged with multiple firearm offences.

In Wollongong Local Court today defence lawyer Oussama Elfawal did not apply for bail for his client and bail was formally refused.

According to the police charge sheet tendered to court the accused was carrying a 1941 bolt-action rifle and an unregistered replica automatic rifle.

Police claim the accused used the WWII-era weapon to fire an eight-millimetre round into a home in nearby Mount Warrigal.

The accused allegedly then proceeded to detain two staff members at a nearby dive shop before contacting police.

The staff were released a short time later, uninjured, before police arrested Mr Fleming.

Weapons, images and videos

Following the arrest police searched his Windang home where they say they discovered two unsecured firearms, five gel blasters, military knives, six replica handguns and a police uniform.

Police also allegedly uncovered more than 1,600 child abuse images and two videos.

Mr Elfawal told the court his client required medication which had been supplied to corrective services.

"Could I ask that Corrective Services continue to arrange for Mr Fleming's medical needs to be met," he said.

The matter has been adjourned until February.