New Zealand 10-year-olds are among the highest climbers in a world chart of mathematics performance - but are still registering as average.
The Year 5 students were among just six nationalities of 25 recorded as showing "significant improvement" in maths in the Trends in International Mathematics and Science Study.
Thefigures are compared with performance in a similar study in 1994-1995.
It puts Kiwi Year 5 maths students 11th on the table - on a par with their Australian and Scottish counterparts, but still performing well below the United States and England, the biggest improvers.
National Year 5 research co-ordinator Megan Chamberlain said the original study had showed New Zealand was not performing well.
The responses, which included professional training, numeracy projects and assessment tools, were now taking effect, said Ms Chamberlain.
Year 5 students also showed a marked improvement in science achievement - one of just nine countries to do so. In tests the children proved to be performing "significantly above" the average.
Secretary for Education Howard Fancy described it as "good news" and said programmes to lift ability in primary schools were bearing fruit.
But it was not such good news in a joint study of Year 9 students who have failed to lift their achievement in maths and science.
But that is partly because in the original study they were already performing significantly above the average of 46 participating countries.
They are continuing to hold that position, which puts 14-year-olds alongside Australia and the US in maths, but "well below" 13 other countries including Japan, Belgium and the Netherlands.
Fiona Sturrock, national Year 9 research co-ordinator, said it would be "two or three years" before this group started to see the benefits of intervention, which had been aimed at primary schools.
Mr Fancy said one of the most important trends the study revealed in New Zealand was a narrowing of the gap between the top and bottom performing students.
