Police has asked social media users to stop sharing graphic footage circulating online relating to the incident in Christchurch.
"We would strongly urge that the link not be shared. We are working to have any footage removed," the New Zealand police said.
Police earlier told CNN they were "aware" of a specific video, but were unable to confirm or deny its veracity.
The disturbing video which has not been verified by CNN, purportedly shows a gunman walking into the mosque and opening fire.
CNN is choosing not to publish additional information regarding the video until more details are available.