Not one student at Gloriavale school has gone beyond Year 11 in the past three years and they have only 17 subjects to choose from, sparking fresh calls for an investigation.
Documents obtained by the Herald on Sunday show the 45 senior students who went to the fundamentalist Christian community's school in 2012, 2013 and last year finished their education around the age of 16, the earliest children can leave school under New Zealand law without special Ministry of Education permission.
The documents also reveal the students have a range of 17 subjects, compared with a choice of at least 35 at a typical state school.
Secondary Principals' Association of New Zealand president Sandy Pasley was disturbed at the "woefully inadequate" curriculum.
Any pupils who wanted to leave the community would be ill-prepared for higher education with such a basic standard, she said.
A move to get the Education Review Office (ERO) to investigate the narrow syllabus was stonewalled last month by a Parliamentary select committee. The ERO maintained all the children learned to read and write and the remote school on the South Island's West Coast was not breaking any laws.
Green Party Education spokeswoman Catherine Delahunty said the right of the child, especially girls, to a broad education was being ignored. "The Government needs to protect these girls right to a proper modern education, not fund this Victorian-era throwback."
Gloriavale principal Fervent Stedfast defended the level of instruction. "All we do is fully in accord with the Ministry of Education," he told the Herald on Sunday.
The documents showing NCEA results, released under the Official Information Act, show pupils are taught the minimum Level 1 maths and English standards, and girls are excluded from science.
Other Level 3 subjects are strictly trade-related and segregated by gender. Large numbers of boys achieve standards from the agricultural or construction syllabus, while girls take cooking, pattern-cutting and childcare.
The school's website reveals all 15-year-olds at the Haupiri compound are expected to spend their last year at school in work experience and part-time study as preparation for community life.
The variety of secondary education alarmed Delahunty who believes the ERO and the Government needs to take a second look at the school. She will go to Gloriavale in coming months to speak with women.
Delahunty said the Education Ministry injected nearly $200,000 into the school last year and she would be questioning officials about further funding.
To pass NCEA Level 1 a secondary student must achieve between four and six standards in English, science and maths plus two or more optional subjects to achieve 80 credits.
Pasley said maths and science were core subjects in secondary schools and it was distressing to see girls denied access.
ERO chief review officer Iona Holsted said Gloriavale met the legislative criteria for registration and parents were free to have their children learn using the curriculum adopted by the school.
"The skills provided at Gloriavale - literacy and numeracy, problem-solving and work ethic - are skills that are transferable beyond the community."