Democratic New Jersey lawmakers were already moving to have the state ban "ghost guns" that you can assembly with untraceable components at home.

Now, they've amended their plan to propose banning controversial 3D-printable guns, as well.

The updated bill began moving through the state Legislature on Monday, with the state Assembly Judiciary Committee voting to approve it, 4-1, with one abstention.

State Sens. Joseph Cryan and Nick Scutari, both D-Union, introduced the original bill in April. It would prohibit the purchase and assembly of untraceable firearm components used to make homemade guns without serial numbers.

Now, the legislation (S2465/A3129) would prohibit people from disseminating programming files used by 3D printers to make plastic guns.

The sponsors say it would be the strongest such law in the U.S. if passed by the Democrat-controlled state Legislature and signed by Gov. Phil Murphy, a Democrat.

"The dark side of new technologies is that people can make firearms at home that are undetectable and untraceable," said Cryan, D-Union, the former sheriff of Union County.

"This allows people who are a danger to others or themselves to get their hands on firearms, including felons, people with mental illnesses or those who have been convicted of domestic violence. Our laws need to be updated to keep pace with new technologies and methods that allow the unchecked spread of these lethal weapons."

Gun-rights advocates say the measure is redundant because it's already against state law to manufacture a firearms without a state manufacturer's license and that people prohibited from buying guns are also barred from assembling guns.

3D-printable guns became the subject of a national debate this summer when a Texas group said it planned to publish schematics for homemade guns online.

In New Jersey, Murphy's administration got involved in nation-wide lawsuits to stop it.

The "ghost gun" bill already passed the state Senate in June, 37-0. But the Senate would have to vote on the measure again now that it's been revised.

It would also need to be approved by the full Assembly before Murphy can consider whether to sign it into law.

Murphy has not weighed in on the legislation. But the Democrat has signed a number of measures to tighten the state's already strict gun laws and has vowed to make New Jersey a national leader on gun control.

Brent Johnson may be reached at bjohnson@njadvancemedia.com. Follow him on Twitter @johnsb01. Find NJ.com Politics on Facebook.