New Zealand hockey representative and all-round sportswoman Emma Rainey took out the U19 girls race, while Louis Hogan beat home his brother Flynn in the U19 boys.
Murphy suggested the majority of the podium-finishing athletes in each grade would gain selection for next week's event.
WHS Results: U15 Girls Rebecca Baker 1st, Amber Andrews 2nd, Sara Stuart 3rd.
U15 Boys Travis Bayler 1st, Sam Luff 2nd, Connor Munro 3rd.
U16 Girls Kayla-Lee Wainwright 1st, Monique Cleeve 2nd, Rebekah Chamberlain-Butters 3rd.
U16 Boys Loris Knigge 1st, Logan Hughes 2nd, Jonty Thomson 3rd.
U19 Girls Emma Rainey 1st, Kate Malcolm 2nd, Hollie Brasting 3rd.
U19 Boys Louis Hogan 1st, Flynn Hogan 2nd, Jack Pilet 3rd.