The New South Wales Police Commissioner says he is worried about the increasing ease with which Australians can make handguns quickly and cheaply using 3D printers.

At a national law enforcement conference in Darwin today, Andrew Scipione warned his interstate counterparts about the technology.

He told the Standing Council on Police and Emergency Management that easily downloadable blueprints for a plastic gun known as the 'Liberator' were recently made available online.

He said the guns, which could be made in hours for as little as $30, had been tested by NSW Police.

He showed a video of one of the weapons being fired and its barrel exploding upwards.

Commissioner Scipione said the guns could risk lives.

"We know that they [blueprints] were filed, downloaded into Australia," he said.

"We know that there are many people who have access to these types of printers.

"If we had a situation where somebody made one of these things and thought that it was a gun that would only go one way, they would be in for a rude surprise."