Keira led a Girls' High one-two in the East Coast regional competition, with Johelonn Toroa-Taare placing second.
No live competition was held this year due to Covid-19.
Instead, students submitted videos of their performances.
Keira and Johelonn will now submit another video of two songs to compete for a place in the Smokefreerockquest national finals in Auckland in September.
Meanwhile, groups have until Friday to submit their videos for the band section of the competition.
Regional winners will be announced on August 7.
Keira enjoyed combined success earlier this year. She and Girls' High student Malia Suluka co-wrote the song Enough, which won youth music support organisation Play It Strange's peace song-writing contest.