A man has appeared in court charged with assaulting a person in a family relationship after a woman and two children were killed in Rotorua.

Police earlier said they arrived at a property on High Street in Glenholme shortly before 10.30pm on Monday, where they found two dead children and a woman with life-threatening injuries. The woman died at the scene.

Police said a man was assisting police with their inquiries.

On Tuesday, a man aged in his early 20s appeared in the Rotorua District Court charged with assaulting a person in a family relationship.

The court heard that court documents named three victims. The man, who appeared via audio-visual link, was wearing white coveralls.

The man, and the victims, were granted interim name suppression.

The man was remanded in custody until 2 October.

A relative of the man declined to comment when approached by RNZ.

Earlier, Bay of Plenty acting district commander Inspector Logan Marsh said it was an "incredibly traumatic incident for all those involved".

"Our focus now is on supporting the family, our first responders and getting answers to what occurred last night," Marsh said.

"We know this event will be felt widely in the community and people will want answers. We are methodically working through the scene, including a detailed forensic examination."

He said this could take several days and there would be a police presence in the area.

"We know people will be understandably shaken following this incident and police will be carrying out additional reassurance patrols over the coming days and nights in Glenholme and the wider community.

"Out of respect for the victims and their family, we ask that people refrain from speculation or conjecture. Our focus remains on establishing exactly what occurred and providing answers for those affected."