The legislation, to be introduced to Parliament this week, aims to curb gun violence across NSW by giving police "wide ranging new powers to search for firearms and target criminal hangouts".

It means police will be given the power to detain individuals subject to firearm bans and search their vehicles and properties without a warrant.

The penalty for the possession and/or supply of a firearm for a person who is subject to a firearm ban will also increase from 10 to 14 years in jail.

Kernaghan and Associates principal and member of the Illawarra Law Society Aaron Kernaghan said the legislation created a "fiction" whereby the public were being misled into thinking police needed more powers than they already had.

"If police can stop people without a warrant or without having proper suspicion that something illegal is going on, how would that be in any way different to living in a police state?" he asked.

"People who carry guns are going to carry the gun whether police can search them with or without a warrant."

Premier Barry O'Farrell said tackling gun crime was a "key priority for the NSW government".

"The community rightly expects people who use illegal guns to be caught and to face the full weight of the law," Mr O'Farrell said.

Firearms have allegedly been used in at least two separate armed robberies in the past week in the Illawarra - one at Bomaderry and the other at Port Kembla.

However, NSW Bureau of Crime Statistics and Research two-year trend data shows rates of prohibited and regulated weapons offences for the Wollongong, Shellharbour, and Shoalhaven local government areas are stable.

Shellharbour recorded the worst rate of offences, at 228.6 per 100,000 people, while Kiama was the only Illawarra council to have recorded a lower offence rate (110) than the state average of 113.3 per 100,000.