Police and paramedics were called to the home at Sunnybank Hills on Wednesday where one of the six-week-old pair was confirmed dead.
Her twin was transported to hospital in a critical condition, but police say she died on Thursday.
Their deaths are not being treated as suspicious, reported AAP.
When emergency services arrived at the scene they rendered first aid to both baby girls.
One of the children could not be saved and died at the scene.
The other twin was transported to hospital.
Preliminary investigations suggest the babies were sleeping together throughout the night and were discovered unresponsive in the morning.
The Courier Mail earlier reported that the babies may have been in a bed with their mother when the incident occurred.
However, police would not confirm initial reports the babies were injured after becoming covered with bedding while in bed with the mother.
A neighbour told the publication she could hear the father “howling and screaming” as an ambulance arrived to the home this morning.
Other neighbours told Channel 7 two other children live at the home and that the family always seemed happy.
A report will be prepared for the coroner.