A person who worked closely with Brenton Tarrant says he is the man in a video and social media speaking about the Christchurch attacks.
The New South Wales woman said Mr Tarrant worked for her in the city of Grafton up to seven years ago as a personal trainer at a gym.
She said she was lost for words.
When Mr Tarrant worked for her, he didn't show any signs of extremism or racism.
She said that when he left Mr Tarrant had expressed a desire to travel, but she did not know where.
The woman said she sent her love and heartfelt blessings to New Zealanders.
Australian ABC News reporter Claudia Jambour is in Mr Tarrant's home town of Grafton in the Northern Rivers region of New South Wales.
She told RNZ the Tarrant family was very well respected in the town.
"We don't know if they're (Mr Tarrant's family) is still living in Grafton at this stage, however, like I say, they are very well known in Grafton, Grafton is a quite a small community of about 30,000 people," Ms Jambour said.
She said the region wasn't known for its radical views.
"It's a very wholesome, friendly regional community, it's very tight-knit.
"As the old saying goes, everybody knows everybody in a small town, it's not known for that at all."
Ms Jambour said the news is still rippling through the community.
"We've spoken with a few people who said they're upset and deeply shocked."