Cullinane whipped Wairoa College 58-14, Manawatu College 45-21, and beat Rua Mano (34-20) and Makoura College (40-24).
Both teams are now poised to advance further today and tomorrow in the top eight play-offs against sides yet to be determined.
Nga Tawa, WGC and TAS have had mixed results since Monday without winning enough to make their respective top eights. All three are now in the playoffs in the bottom-16 section that also continues over the next two days.
WHS coach Lisa Murphy said there was no disgrace in being beaten by St Mary's Wellington, a side she described as a "beautiful, classy" team.
"St Mary's are the defending national secondary schools champions and are a beautiful and classy team to watch and play against," Murphy said.
"The girls played well and did all they could against St Mary's, but they were simply too strong. We finished sixth at this tournament last year, so we'll be looking to improve on that over the next two days now we are assured of a spot in the top eight."