TOKYO (AFP) - Weak public spending on education in East Asia is leaving families to pick up the tab, heaping huge burdens on parents who want to get children through college, a new global report has found.

Improving academic results, particularly in maths, are being underwritten by pricey private tutoring despite the society-wide benefits of a better-educated population, the Organisation for Economic Co-operation and Development (OECD) said.

A common challenge for the region's governments is "to build better systems of public support to enable talented people from all sorts of backgrounds to take part in higher education", said Mr Andreas Schleicher, director of education at the OECD.

"East Asian countries spend relatively limited public budgets for education," he said during a video conferencing for Tokyo-based journalists. "A lot of the burden for financing of education, particularly higher education, (falls on) parents, families. That's a chronic trend among East Asian countries," he said.

In Japan, 30.5 per cent of money spent on education across all levels comes from private sources, the OECD found in its Education at a Glance 2014 report. In South Korea, the figure is even higher, at 37.2 per cent.

These compare with an OECD average of 16.1 per cent. European countries tend to have a higher proportion of the cost of education borne by the public sector, with 97.2 per cent of Sweden's education bills picked up by the state.

The private contribution to the cost of tertiary education alone - university or college - in Japan and South Korea is even higher, at 65.5 per cent and 73 per cent respectively. This compares with an OECD average of 30.8 per cent.

The report also highlighted a 2012 finding that 15-year-olds in East Asia do better in maths than their peers elsewhere, despite relatively smaller public spending on education.

In 2012, students in Shanghai, China, had the best global score in the subject, followed by those in Singapore, Hong Kong, Taiwan and Korea.

The value that society places on education is a clear benefit to the ultimate performance of these students, said Schleicher, even though this does not always show up in public spending commitments.

"Children from all sorts of backgrounds take part in education and achieve good results, despite relatively weak public support systems," he said.

"I actually attribute that largely to high values that families, parents and everyone and teachers place on education, much more so than the rest of the world," he said.