An expert in the technology of 3D printing has questioned fears it could spark a mass proliferation of homemade guns on Australia's streets.

3D printers - available for less than $1,000 - work by printing layer upon layer of plastic, building objects from virtual blueprints.

New South Wales Police Commissioner Andrew Scipione yesterday warned more than 100,000 firearm blueprints have now been downloaded worldwide, giving people the ability to build their own guns.

"There are no standards around the manufacture of these weapons. They are truly undetectable," he said.

"They are untraceable because they no serial numbers, no unique identifiers. They are cheap, and easy to make."

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Dr Robert Gorkin from the University of Wollongong is researching the use of 3D printing to recreate human tissue.

He does not think a mass proliferation of home-printed guns is likely.

"There's a concept that there's a fully printed gun that you can just go online and download it, and it's ready to go, and if I buy a home printer I can actually do that," he said.

"That doesn't exist right now."

Dr Gorkin says even high-end printers have not been able to produce a gun that is reliable, accurate, can be repeatedly shot, and will not possibly explode when fired.

"You can print parts of guns and put them together," he said.

"But right now there's nothing that you can just download a file, have a printer - not even the high-end printers - and print a complete assembled gun that will act like something you can buy in a store.

"The technology now is not going to necessarily lead to these surges in home-built guns.

"There's plenty of other ways to make a weapon if you really want to.

"It's really not the most efficient way."

But Dr Gorkin says that technology is developing rapidly.

"It's impossible to say that it'll never happen," he said.

"I do think that some of this conversation is relevant... but I think that discussion should be made with a reasonable analysis of where the technology is."