New Zealand's university system has ranked seventh best in the world in the annual Universitas 21 league table, but only after allowing for the size of the economy.
The ranking was based on factors including government spending, research, and the independence of universities to run their own affairs.
The raw ranking put New Zealand's eight universities in 15th place, with the United States first and Australia in tenth position.
But adjusted for GDP per capita, New Zealand rose to seventh with Serbia leading the table, followed by the United Kingdom and South Africa, while Australia retained tenth place.
The Universitas 21 league table is one of many ranking systems, but focuses on each country's overall higher education system rather than on individual institutions.
The Universitas 21 report said since 2013 New Zealand had fallen six places in the raw rankings largely because the number of tertiary-qualified adults had risen faster in other countries and overtaken New Zealand's score in that part of the measurement.
Ranking adjusted for GDP per capita
2 United Kingdom
3 South Africa
7 New Zealand
1 United States
3 United Kingdom