The warm temperature inside a van where a baby girl had been sleeping with her mother might be a factor in the child's death, police say.
Officers were called to a property in Waiuku in Counties Manukau yesterday after the "sudden and unexplained" death.
A post-mortem this morning was inconclusive as to the cause of death.
Acting Detective Inspector Colin Higson said the mother and baby had been sleeping in the van while their home was being renovated, and police were looking at whether the temperature in the van had contributed.
However, he said that had not been confirmed and there would be further investigations.
"Understandably, this is a very stressful time for the baby's family and her death is an absolute tragedy for them."
He said, while the incident was still under investigation, it was a timely reminder about the dangers of leaving children in vehicles during warm months.