Police were called to the shooting about 3.30pm.
A gun was recovered at the scene and police were speaking to family members believed to have been present when the shooting occurred.
The woman's body tonight remained at the house, which would be guarded overnight, and would be removed tomorrow for a post-mortem examination.
Police appealed for sightings of a car driven from the woman's home and stopped by police in Waitara late this afternoon.
We would like to hear from people who saw this car travelling between the remote settlement of Okoki and Waitara between 3.30pm and 5.30pm tonight," Mr Coward said.
"We have a lot more inquiry work to do, and people can help us with
sightings of the car.
"This is a stressful and emotional time for people who were present at the
house, and others in the community."
The boy is to appear in New Plymouth District Court tomorrow.