Gun control activists have expressed concern over a growing firearms "sub-culture" in Sydney's north, as latest numbers reveal the owners of four of the top-12 largest individual arsenals in NSW live in the area.

The person who owns the highest number of firearms in the whole of NSW now lives in Cremorne, with 314 guns to their name.

Andrew Tomic, 34, has a collection of firearms he sources from the upper north shore. Credit:Steven Siewert

The latest figures released by the NSW firearms registry show a resident in Mosman owns 297 guns, while a Terrey Hills resident owns 219 guns. A resident in Belrose has 181 guns in their private arsenal. The numbers exclude collectors and dealers.

President of the NSW Gun Club in Terrey Hills Joan Robertson said the community of local shooters was "wonderful". As for the large numbers of guns owned by individual licence holders in the area, Ms Robertson provided simple reasoning.