Police have said an autopsy and other information they had gathered indicated Maree had died of ''non-accidental injuries".
Maree Takuira Mita Ngahere died in Kaitaia last month. Photo / NZ Police
Acting Detective Inspector Lloyd Schmid said a team of detectives were speaking to a large group of people in Northland - and further afield - in relation to the newborn's death.
"We are making progress and we are grateful to those members of the public who have contacted police as a result of our appeals for information and have assisted our investigation," he said.
"These are very serious injuries inflicted upon an innocent baby less than 4 weeks old.
"The very nature of those injuries are deeply concerning.
"I continue to urge anyone who has yet to contact police to come forward as we know there are people out there who hold vital information about this case."
* Anyone with information about the case is asked to contact Kaitaia Police on (09) 408 6500 or anonymous tip line Crimestoppers on 0800 555 111.
