In an attack broadcast live on Facebook, a lone gunman armed with semi-automatic weapons targeted Muslims attending prayers in two Christchurch mosques on March 15, killing 51 people and wounding dozens.
Australian Brenton Tarrant, a suspected white supremacist, has been charged with the attack and faces trial next year.
Chief Censor David Shanks said a video game that celebrated the livestream of the mass shooting has been classified as objectionable.
"The creators of this game set out to produce and sell a game designed to place the player in the role of a white supremacist terrorist killer," Shanks said in a statement.
"In this game, anyone who isn’t a white heterosexual male is a target for simply existing."
Shanks previously outlawed the livestreamed video of Christchurch attack, and a manifesto linked to the alleged shooter.
Earlier this month, the censor board also outlawed a 35 minute long video of another attack by an anti-Semitic gunman who killed two people in Halle, Germany.
A document said to have been shared by the gunman in Germany has now also been banned, Shanks said.
Some game producers appear intent on producing a 'family' of white extremist games, and have established a revenue stream from it, with customers in New Zealand and around the world able to purchase the games from the producer’s website, Shanks said."The games producers will try to dress their work up as satire but this game is no joke. It crosses the line."