It was an ambitious asking price for an item crafted in the loungeroom of his apartment in Sydney's eastern suburbs.

And while the advertisement for a 3D printed gun didn't yield any buyers, it did grab Sicen Sun the attention of police.

In early February, police allege the advertising agency accounts manager made a post on Facebook, offering the imitation firearm for the cool price of $1 million.

Mr Sun, a UTS graduate and former Apple computers techie, had allegedly printed the firearm using 3D printers inside his Waverley unit.