"If you look at the system from when a child starts school to when a child leaves school, the hole in the system in terms of the absence of an assessment tool is Year 9 and 10," Ms Parata said during a question and answer session at the NZ Principals Federation conference.
The Ministry of Education had identified three assessment options:
• Expand National Standards to Year 9 and 10.
• Roll NCEA down from its usual start at Year 11.
• Use a modified youth version of the Literacy and Numeracy for Adults Assessment Tool, an online approach that provides information on reading, writing and numeracy skills.
"We pretty much have got to the point where we have said, well, it's one of those three options," Ms Parata said.
Schools would be able to choose which option worked best for them, and that decision could be made initially by "communities of schools" formed under the Investing in Educational Success programme.
The scheme uses $359 million over four years to group local schools, where principals and teachers are paid extra to collaborate.
"There is not going to be an arbitrary determination that this shall be the way that this occurs," Ms Parata told the Herald.
"In different communities of schools they might decide, well, we are going to extend national standards to Year 10, and our [secondary school] subject specialists will teach subjects like maths into primary school."
Asked when schools could choose an assessment option, and whether continuing with the status quo would be an option, a spokesman for Ms Parata said it was "very early days".
Secondary Principals' Association president Sandy Pasley said assessment at Year 9 and Year 10 had been mentioned only in passing to the association.
"This is the first I have heard of NCEA coming down to the lower levels."
Ms Pasley said she suspected some secondary schools and teachers would object to National Standards because of ongoing issues with consistency, and there would also be some concern at NCEA expanding.
"There is a huge danger of over-assessing and not having enough time for just teaching."
Patrick Walsh, principal of Rotorua's John Paul College, said expanding NCEA potentially had merit, and many schools already let brighter students work towards it early.
"But it would create workload issues for teachers and students, and increasing pass rates suggested there was no problem to solve.
"All the research seems to indicate that the major concern that we have in the New Zealand education system is in fact that we overly assess.
"There's an argument to say, well, let's just focus on learning in Year 9 and 10."
