The 28-year-old, who is from Grafton in NSW but moved to Dunedin two or three years ago, allegedly shot and killed 50 people in two mosques during a rampage he filmed and livestreamed.
He was arrested shortly after the attack and has been charged with one count of murder. Further charges are expected and he did not request bail on Saturday.
In Facebook posts obtained by news.com.au, one hunter described a shooting session between Tarrant and his friends at a remote rifle club south of Dunedin as worrying.
The post, from November 2017, talks about members of the rifle club and how “one in particular had me really worried”.
News.com.au has confirmed the man being referred to is Brenton Tarrant.
It reads: “He was complaining about skateboarding kids at the uni saying if they can carry their boards then he should be allowed to carry a gun.”