A male relative of the homeowner searched under the house, where he found the woman, before calling emergency services to the Miller Street home just before 7pm on Saturday.
It is believed the woman crawled under the house and became trapped.
A spokesperson for the Metropolitan Fire Brigade said the woman, aged in her 30s, was rescued after firefighters cut a hole in the kitchen floor before 9pm.
An Ambulance Victoria spokesman said another neighbour heard the woman calling out and alerted authorities.
The rescued woman reportedly told emergency service workers she was under the house for four days.
She had suffered some exposure to the cold and was taken to the Royal Melbourne Hospital in a non-life threatening condition.
Police say they don’t know why she was under the floor and they are now investigating.