Police and St John were called to the address on Shortland Street at 8:45pm, and on arrival found the woman in critical condition.
A manhunt for the shooter is currently underway with police reporting they escaped in a vehicle.
"Enquiries are ongoing today to locate the person responsible" Police said.
It's been reported that the woman gunned down in Wainoni last night was shot through a fence.
Police said a scene guard was stationed overnight.
A police presence is expected in the area for some time.
More to come...