Police are investigating how an 18-month-old girl suffered "non-accidental injuries" after an incident near her Hamilton home.

The toddler remains in Waikato Hospital with moderate injuries.

Waikato Police Detective Senior Sergeant Nigel Keall said police were called to the incident last night and discovered the injured girl through "good police work".

The initial incident was not at the girl's home in Fairfield's Halberg Cres, but in a public place.

Advertisement

"We weren't initially called to the address. We were called to an incident and some very good police work identified that this child was injured."

When she was located by police, the youngster was taken to a medical centre and on to Waikato Hospital's emergency department.

Keall said police were sufficiently concerned over how the girl sustained the injuries to launch an investigation.

"It appears the incident has occurred at a home in Hamilton and so currently we've completed a scene examination and we're speaking with family members who were home at the time to ascertain exactly what has occurred."

He said the girl lived at the Halberg Cres address with immediate and extended family members including siblings but he would not say how many people lived there or whether the other children were still in the care of the family.

Keall would also not elaborate on what the injuries were but said though they were not life-threatening they were "certainly not minor".

"It's really sad."

He expected inquiries to take several days at least and said the investigation was progressing well.