Devereux (16), a pupil at St Hilda's Collegiate School, won the gold medal in the girls aged 16 to 18 synchronised dive with Kayla Forket (Hamilton) with 186 points.
She also won silver medals in the same age group in the 3m with 270 points and the platform with a personal best 268 points.
She was fourth in the 1m.
Devereux switched from gymnastics to diving four years ago and this was her first time on the podium at a national championships.
"I'm pretty happy," she said.
"But there is always room for improvement."
There has been a significant improvement in her diving over the last few months.
"I've changed my take-off from three steps to a hop and a step like the Chinese divers," she said.
Devereux demonstrated her potential when she finished in the top 10 at the Australian age group championships in Adelaide in April.
She will have another crack at the Australians when she competes in the School Games in Sydney in August. She contested the same event last year and this will be the third time she has competed in Australia.
"I want to compete at a higher level and gain experience," she said.
She is working hard at her sport under the direction of her coach, Becky Marquet. She spends 10 hours a week on diving - two days on land and three days in the pool.
The coach rates her potential highly.
"Genevieve is not afraid to try new things," Marquet said. "She is able to manipulate her body in the air to get a quality dive.
"There is no-one better than her in the South Island."
Devereux enjoys the challenge of an individual sport like diving where the onus is on her to produce the goods.
"People in diving are like family. Everyone is so close and support each other."
