Erika is trained by her mother, Miho Davis, a teacher at the school.
"Karate was quite tough but very interesting and rewarding," Erika said.
Erika will hold the world title for two years until the next Shito-Ryu which will be held in Western Australia.
She admits being very happy but going on to eventually compete in an Olympic Games probably won't be an option though.
"Because the training is very strict and my mother won't have time to train me. I don't mind at all."
Erika said she had grown up a martial arts baby, learning techniques from the time she could walk.
"I have been practising the Shito-Ryu Karate discipline intensely since I was 3. I was
giving private lessons when I was 11.''
Her mum, Miho Davis, has five black belts, is a master Shito-Ryu instructor and runs the Davis Karate Academy in Feilding, where they live.
Miho also teaches maths, science and art at Taihape Area School.
"We are busy,busy," Miho said.
Erika is very proud of her Maori/Japanese heritage and says it has contributed to her strength and resolve. She said she was a fierce competitor "and Karate is a lifelong discipline", she said.
She plans to study law after she leaves school and, preferably, work with young people.
"And I will still be competing in karate. I will never let that go."