NSW will have a million firearms by the end of the decade, a rate of growth that a Greens MP warns could encourage a local version of American gun-ownership culture.
New Police Firearms Registry data shows an extra 65,000 firearms were registered in NSW in less than two years, bringing the state's total pool of legal guns to 915,000.
If current growth holds, there will be more than a million guns registered across the state.
"People are often shocked when they hear how many guns there are in NSW and they have every right to be," Greens MLC David Shoebridge said. "We must not go down the US path of more and more guns until we are so saturated with firearms that people start demanding guns to defend themselves from guns."
Robert Borsak MLC, of the Shooters, Fishers and Farmers' Party, accused the Greens of stoking fears about guns owned by law-abiding people and which were heavily restricted.
"There's no resemblance to what you would find in America, where they have AK-47s, Kalashnikovs and machine guns," he said
The figures come as Australia begins its first national gun amnesty scheme since former prime minister John Howard overhauled the nation's gun laws after the 1996 Port Arthur massacre.
A three-month federal government amnesty was announced by federal Justice Minister Michael Keenan on Friday.
He said the measure, which will receive Labor's support, was an attempt to reduce the pool of illicit weapons that had been used in terrorist attacks such as the Lindt cafe siege and the shooting of NSW Police employee Curtis Cheng.
"We've got an environment where there has been five terrorists attacks on our soil and, sadly, in the vast majority of those cases it has been an illegal firearm that's been used," Mr Keenan told the ABC.
Estimates on the number of illegal firearms circulating on the Australian black market range into the millions but a recent study by the Crime Intelligence Commission put the number at at least 250,000.
About 1400 legally registered guns were stolen in NSW over the past two years.
Recent Sydney University research found that in recent decades the proportion of Australian households with a firearm had fallen drastically but suggested people who possessed firearms were now buying more of the weapons.
Mr Shoebridge said the recent data showed individuals had been stockpiling weapons.
"There are eight private individuals in NSW who each have more than 200 guns a piece, with one owning 312," he said.
The figures exclude dealers and collectors.
Griffith University's Dr Samara Mcphedran said rising legal ownership had been complemented by falling levels of firearm violence.
"Firearm violence in NSW is very uncommon," she said.
The Howard government's amnesty collected about 650,000 weapons including semi-automatic style weapons.
NSW has implemented more than a dozen different amnesty or buyback schemes in the past three decades.