Under NSW legislation, police officers are required to enquire about and seize any firearms from a dwelling where domestic violence has occurred.

Lake Illawarra police Licensing Sergeant Gary Keevers said seized guns are kept by police for a 28-day "cooling off period," and are only returned after an assessment by the NSW Firearms Registry.

"Our officers are seizing firearms from domestic violence incidents on a weekly basis," Sergeant Keevers said.

"After further inquiries, sometimes firearms are returned to the owner."

The NSW Police Force's Code of Practice for domestic violence states firearms must be seized from any family violence situation, no matter whether they belong to the victim, offender, or any other person in the home.

"Regardless of whether it was used [in domestic violence], police must seize any firearms that either party involved in the incident has access to," the document said.

If an Apprehended Violence Order is issued, firearms licences can be suspended or revoked.

Sergeant Keevers said the provisions aimed to ensure situations did not escalate to a deadly conclusion.

"When people are arguing, you don't know what could happen," he said.

There are more than 10,000 registered firearms in the Lake Illawarra local area command, and Sergeant Keevers said most gun owners comply with legislation.

Lauren Huggett, support worker with Lake Illawarra Family Violence Support Service, said laws helped halt escalating violence.

"Women tell us the threat of a gun is often used, so once the gun is out of the situation, it can alleviate some stress," she said.

"Some say their partner sleeps with a gun under the pillow. If someone is aggressive or violent, they shouldn't have access to guns."