She will be sentenced on August 1. The children are not currently in her care.
A police summary of facts said the children were hungry and cold - the 8-month-old was filthy and in desperate need of a nappy change.
No food was in the refrigerator.
Police found a packet of sausages in the freezer and rummaged up a loaf of bread and made toast for the children.
Dirty blankets and empty bourbon and cola cans littered the floor. Two single beds had no linen.
Gage was charged after police knocked on her door and discovered her children on Saturday, May 10.
Officers had been in Gage's street in Raumanga on an "unrelated matter". Initially, the children refused to open the door. One yelled "who is it" before they screamed for their mother.
Police entered through an unlocked back door. A neighbour helped tend and feed the children and change the 8-month-old after no baby-care products or baby food could be found in the house.
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