The new data showed small improvements by Maori and Pasifika students in years 1-8 in reading, writing and maths. On average the performance of Pasifika students improved 3 per cent.
However, Maori and Pasifika students still trail other students, and boys continue to perform worse than girls.
The Ministry of Education has established an advisory group of literacy and numeracy experts to analyse the data and make recommendations on how to improve the results.
"We expect school leaders and teachers to use their data and to be targeting resources to the areas where extra support is needed," Ms Parata said.
However Mr Clark said he didn't believe the data would help the ministry improve the way it targeted funding.
"They're going to allocating funding on inaccurate data. The data is still inaccurate, it is still too variable."
Mr Clark, principal of Whau Valley School in Whangarei, said data from his school data was more reliable than the national data the school had presented to the ministry.
"I do have National Standards data here, and I also have our own school data - they are similar, but I know which one I make my decisions on - the more accurate one is our own school data."
This is the first year National Standards data was available by school year. It showed what Ms Parata described as "concerning trends", including a decline in achievement as the year level increases, especially in mathematics.
However she said that overall the results were a "pleasing advance on last year's data".
It was split year by year and there had been a "small but incremental increase in reading, writing and mathematics results".
Waikato University professor of education Martin Thrupp said the claim that there had been an overall national improvement was "unsound" because the national data reflects such "highly variable and changing factors".
National Standards in reading, writing and maths show what all New Zealand children are expected to be able to do by the end of each stage during years 1-8, as part of what they learn at school.
The ministry is still working with 415 of New Zealand's 2300 schools to ensure their data is correct.
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2012 national aggregate data shows:
- Reported achievement against the National Standard for reading increased from 76.2 per cent in 2011 to 77.4 per cent in 2012.
- Reported achievement against the National Standard for mathematics increased from 72.2 per cent in 2011 to 73.6 per cent in 2012.
- Reported achievement against the National Standard for writing increased from 68 per cent in 2011 to 70 per cent in 2012.