A deadly terrorist attack it was. We generally see candle marches across the world in response to such incidents.

But at many places in New Zealand and Australia people expressed their anger, anguish and sympathy to victims and their families differently

A Maori biker gang organised a Haka Dance. It is an emotive dance. A posture dance which can move people into extreme emotional states of mind. Some Australian groups performed the dance on beaches. 

Here is a video of students mourning and honouring their peers who died in the Christchurch shooting by performing a Haka.

Here is how Wikipedia explains the Haka dance:

The haka is a ceremonial dance or challenge in Māori culture. It is a posture dance performed by a group, with vigorous movements and stamping of the feet with rhythmically shouted accompaniment. Although commonly associated with the traditional battle preparations of male warriors, haka have been performed by both men and women, and several varieties of the dance fulfil social functions within Māori culture. Haka are performed to welcome distinguished guests, or to acknowledge great achievements, occasions or funerals.