He confirmed that of the roughly 70 pupils who started 2019 in years 7 and 8, 12 had left and gone to other schools.
One of the parents, who asked to remain anonymous, believed the school's ''open learning environment'' focused on teaching social skills at the expense of core subjects.
She also said she knew of two former pupils who had said the school did not adequately prepare them for high school.
Witheford said ''we would argue whether you've got them split, or not split, we're still meeting the needs of those kids''.
''A lot of parents will talk about 'ready for high school' and I always ask, because I've heard that now for 20 years, I say 'for you, what does ready for high school mean?', because normally it can be anything from 'I want my child at a certain academic standard' to 'I just want to know they can cope in that environment with older kids in the mix'.''
The issue was discussed last week in a board of trustees meeting attended by 11 parents. The discussion was held in a public-excluded session, for privacy reasons.
Witheford said the school had not done a good enough job of communicating with parents about how it was meeting the needs of senior pupils, and that would improve.
That would include meeting parents who would have senior children in 2020, and bringing forward the school's biennial community survey, which was sent out on Monday.
''We will be talking to topics they have raised and, in addition, discussing how we meet the needs of children in this age range.''
Witheford said like all state schools, Shotover taught to the New Zealand curriculum.
''This means teaching a comprehensive curriculum that meets the needs of the whole child.''
