The critically-injured infant is fighting for life in Waikato Hospital after being set upon by the animal at an Enderley property last night.
Hamilton City Council animal control manager Susan Stanford said staff were contacted by police shortly after 7pm to attend a reported dog attack involving a baby.
Staff collected the dog and it was now secured at the council's animal control facility, she said.
Further decisions regarding the animal would be informed by the ongoing police investigation.
"This is a traumatic time for all involved and our thoughts are with the families and individuals involved."
Stanford said the council was supporting the ongoing police investigation, and was not in a position to make further comment.
Police today confirmed emergency services were called to a Hamilton address about 7pm yesterday after an infant was bitten by a dog.
St John ambulance said the baby was taken to Waikato Hospital in a critical condition.
