The pair were able to pull Jordan, who was seven at the time, from the inferno.
The Fire Service retrieved Ms Ramirez and Reyna, then aged five, from the bedroom floor.
Ms Ramirez died at the scene, however Reyna was able to be resuscitated and has a made a full recovery, Coroner Smith said.
While the cause of the blaze remains undetermined, Coroner Smith said Ms Ramirez's death was another tragic loss of life from a household fire.
"It highlights the importance of ensuring that households have very good smoke alarm systems operating.
"In this instance, we know that the deceased disconnected one of the alarms on the day of the fire because of the noise emitting from it earlier in the day.''
Ms Ramirez died from smoke inhalation, Coroner Smith found.
His report follows a warning from the Fire Service regarding households without working smoke alarms.
Latest figures show 20 people died in avoidable house fires in New Zealand in the past 12 months - with 80 per cent of the properties having no working alarms.
The most common causes of the fires in the 2012/2013 year included cooking after drinking, faulty appliances or electrical wiring and smoking.
Coroner Smith found the most likely cause of the fire which killed Ms Ramirez was an electrical fault.
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Avoidable house fire deaths:
2007/08: 27
2008/09: 16
2009/10: 20
2010/11: 19
2011/12: 12
2013/14: 20
Source: New Zealand Fire Service