When Rico Mareroa completed a science test earlier this year he was confident he had done well.
But the 12-year-old Tauranga Intermediate School student did not realise he had done the best out of thousands of students from across Australasia.
Rico got the news he had achieved 100 per cent in the 40-question International Competitions and Assessments for Schools (ICAS) science test in August.
The test is run by the University of New South Wales, which offers tests in a range of subjects including digital technologies, science, writing, spelling, English and mathematics.
Rico said he was in shock when he was told he had the top mark and rang his family from the school office.
"When I rang my mum to tell her, she cried," he said.
Rico said he liked to do well at school and getting the top mark in the science test "meant a lot".
Chemistry was one of Rico's favourite subjects, along with maths, and he liked to learn about atoms and elements of the periodic table.
He often spent his spare time reading articles about science, doing his own research and he also enjoyed taking part in sports, especially gymnastics.
Rico had been sitting ICAS tests for the past four years and this year sat five tests including science, mathematics, English, spelling, writing and computer science.
He was awarded a high distinction in computer science which meant he ranked in the top one per cent in Australasia and received a distinction for English which meant he sat in the top 10 per cent.
"Most people don't like taking tests, but I do," Rico said.
Rico's achievement was celebrated on December 1 when he was awarded a gold medal for his first place.
The award ceremony was held at the University of Auckland Business School and Rico's mum and dad were there to cheer him on.
This year more than 980,000 entries were received for ICAS.
100 students from New Zealand and the Pacific region were awarded medals for their outstanding achievement.