Geneva  - About 75 million children globally, over half of them girls, do not receive education, including one third of primary school age children in sub-Saharan Africa, the UN's education, science and culture agency said Tuesday.

The lack of education and inequalities in schooling systems caused poverty and diminished opportunity, according to UNESCO's Global Monitoring Report which said governments had to take action to make improvements.

In general, children from poor countries are three times less likely to attend primary school than children from rich nations, and the education they do receive will probably be of lower quality.

Other factors impacting children's school attendance, even in developed countries, range from their parents' income, their location in rural or urban areas and their socio-cultural group.

"In every country there is a relation between socio-economic status and the education of children," Kevin Watkins, the director of the report told Deutsche Presse Agentur dpa.

Political policies of national governments as well as failures by the international community to follow through on aid pledges to poorer countries were hampering improvements, UNESCO charged.

"Government policy matters an awful lot," Watkins said.

"Most of the countries where we've seen very rapid progress, are countries where there is a strong national commitment" to education, "including investing resources," he added.

The goal to have universal primary education by 2015 was unlikely to be achieved, the report warned, and at least 29 million children from various countries will still not attend school.

Currently, 16 per cent of the world's adult population, the overwhelming majority of them women, remained illiterate.

Moreover, in developing countries, one in three children suffers from malnutrition which has impaired their mental development.

However, 28 million fewer children in 2006 were out of school, compared with 1999, UNESCO said, declaring the progress "dramatic."

The report was released on the opening day of UNESCO's 48th International Conference on Education, called under the banner of "inclusive education," which attracted some 1,400 participants, including government ministers, experts and non-governmental organizations.

According to the organizers, children with disabilities and those from marginalized groups are particularly excluded from the school systems, and the conference, set to last all week, will focus on making education more diversified and open. (dpa)