The Chief Censor is concerned there's already a violent computer game out which lets players re-enact the Christchurch mosque shootings.
The game - which Newshub has chosen not to name - has been out since February, but released a scenario based on the March 15 atrocity over the weekend.
Fifty people were killed when an alleged white nationalist opened fire on worshippers at two mosques in Christchurch. He broadcast part of the attack live on the internet and released a manifesto which contained not just hateful rhetoric, but gamer and internet culture jokes, sparking a worldwide debate on free speech.
"I think this is a real concern, but unfortunately it is not unexpected," Chief Censor David Shanks told Newshub on Monday.
"We know that in gamer culture, from research, there is evidence that in some situations, we can have people with reduced empathy."
The game claims it portrays "Jesus' return to a post-apocalyptic world ravaged by radical socialism and religious fanatics" who try to crucify him.
It took only five days for one fan of the game to request an update based on the Christchurch shootings in the game's official forums.
"We know that there are tools, widely available, to make these sorts of games very quickly and cheaply by enthusiasts. We also know these people have distribution platforms," he said.
The developers claim - somewhat unconvincingly - the game is "family-friendly fun" and a "parody" that "does not advocate support or endorse any political group, ideology, movement, entity or individual(s)".
"There's certainly scope for us to call in games of this kind and classify them and potentially make them objectionable," said Shanks. "We had notification about a game a few weeks ago called Rape Day where we were preparing to go through this process.
"But in this case, I think we're looking at cheap, very quickly produced games that will be quite hard to track on various platforms, and it may be that these games don't reach the threshold for an objectionable classification. We don't know. We would have to look at each one."
The game isn't available on the biggest PC gaming platform Steam, and according to its website the developers have also been banned from taking payment through Paypal, Stripe and numerous other mainstream web portals.
Shanks says the Office of Film and Literature Classification will "reach out to our industry contacts to make sure that they're doing everything they can to stop this sort of content being put up".
People who are offended by it can contact them to register their disgust, or ask their ISP to block it. In the wake of the attacks, a number of New Zealand ISPs temporarily blocked websites known to have been frequented by the alleged gunman.
"Parents will potentially find that their children are encountering these games," said Shanks. "That is an opportunity to have actually quite a serious conversation with your child about what they may see and how they can keep themselves safe."
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