In some countries, up to 80 percent of funds earmarked for education, excluding salaries, are funnelled by corrupt officials, according to the report titled: "Corrupt schools, corrupt universities: What can be done."

The study quoted surveys showing that ghost teachers on school payrolls represent five percent of expenditures for salaries in Honduras and 15 percent in Papua New Guinea.

Corruption in higher education takes the form of bogus degrees, accreditation fraud and fake universities, according to the report that was published on Wednesday.

The number of fake universities on the Internet offering bogus degrees has increased from 200 to 800 between 2000 and 2004, according to the report.

"Such widespread corruption not only costs societies billions of dollars, it also seriously undermines the vital effort to provide education for all," said Koichiro Matsuura, director general of the United Nations Educational, Scientific and Cultural Organisation (Unesco).

"It prevents poorer parents from sending their children to school, robs schools and pupils of equipment, lowers teaching standards an thus education standards generally, and comprises the future of our youth."

Bribe-taking is singled out as a particular problem that is tolerated in many countries, including Cambodia where the government has tacitly acknowledged that it could not keep its teachers and professors without the payments.