Facebook is blocking a site that hosts the schematics for 3D-printed guns from its network amid a larger review of its policies on the controversial technology.

The social media titan quietly began blocking links to codeisfreespeech.com across its platforms — including Facebook and Instagram — last week, according to advocacy group Firearms Policy Coalition.

Attempts to post links to codeisfreespeech.com — which hosts the digital blueprints needed to 3D-print parts for weapons including an AR-15 rifle and a Beretta handgun — on Facebook’s platforms are now met with varying error messages, depending on the platform.

Links to other sites hosting the same files reportedly were still going through on Facebook, but the site said they are actively fine-tuning their 3-D gun policy.

Facebook’s community standards ban “the purchase, sale, gifting, exchange, and transfer of firearms, including firearms parts or ammunition” between users.

A message posted on the homepage of codeisfreespeech.com reads, “Facebook instituted a total takedown and BAN on this site!”

FPC head Brandon Combs told The Post that users first reported the ban around Aug. 1, and claimed that Facebook has ignored their appeals and refuses to talk with them about possible ways to fix the issue.

“Facebook is picking and choosing winners and losers in the marketplace of ideas,” Combs said.

The move comes amid an ongoing legal battle between Texas-based 3-D gun blueprint maker Defense Distributed and the federal government.

The plans were cleared by the feds for online release last month, inviting swift blowback from state lawmakers.

A judge in Seattle issued a temporary restraining order on July 31 again blocking the plans’ online distribution.

A hearing to determine whether the injunction should continue is scheduled for Aug. 21.