Area Commander Inspector Kevin Taylor said it was important trust was placed in the police investigation into Mr Collier's death.
"We appeal once again for calm," he said. "The actions of a minority of people are doing nothing to assist the family, the wider community of Opotiki or the investigation process."
Mr Taylor said it was clear Sunday night's incident had caused some tension in the town.
Whakaatu Whanaunga Trust's Mandy Walker said Mr Collier's death had hit the close-knit community hard, and many people responded in panic. "We're calling for calm. The death of a young person is a tragedy for the community and we're asking people to remain calm and be respectful towards the families involved," she said. The trust has released a video on Facebook, titled Calling For Calm, which shows messages from staff members, and a member of Mr Collier's family, asking for the community to stay calm.
Opotiki mayor John Forbes said he sympathised with Mr Collier's family, some of which he knew personally. "They're a big family, and it's a small town. I played rugby with a few of them years back," he said. Mr Forbes said several Opotiki residents were displeased with the behaviour following Mr Collier's death, which shone a negative light on the town they loved. "We've got some dysfunctional people that are a result of being tossed on the scrap heap years ago, but there's a lot of positive things happening in our community as well."
Police last night said Mr Collier's body had been returned to his family.