Chilean President Sebastian Pinera faced renewed youth anger over inadequate education opportunities in Latin America's most developed market economy.

Chile is the only Latin member of the Organization of Economic Cooperation for Development, the club of the world's industrial countries that includes the United States, Canada, most of Europe, Japan and Australia.

But the country's privately controlled education has provoked the ire of students, teachers and trade unionists who say the system perpetuates privilege for the few.

Protests over inequities in the education system are in a second year and despite Pinera's plummeting popularity the government response has failed to calm the youth.

This week riot police resorted to water cannon to break up protests by thousands of students, their families, teachers and workers.

As before, the government called the protesters hooligans and vandals and accused their leaders of orchestrating riots that damaged the economy.

Santiago's mass transit system was among public properties attacked in this week's riots, in which demonstrators threw Molotov cocktails, looted shops and set buses alight.

More than 75 people were arrested and police said 49 officers received injuries. Casualties among the protesters weren't known but only a few reported to hospital with injuries.

Pinera spokesman Andreas Chadwick said the protesters opened the doors to "vandalism and delinquency" and called them responsible for the unrest.

"How much more should we put up with these illegal marches that call on school takeovers and that threaten a violent August?" Chadwick said. "What does that have to with education?"

Student leaders said Pinera's government still seemed clueless about the kind of appropriate response the protesting youth expect. The students say the government, the private sector and the banks are together in enforcing an unequal system that limits higher education opportunities to Chile's privileged wealthy class, a tiny minority.

Transportation Minister Pedro Pablo Errazuriz said he spoke for "millions of people who use the Transantiago and these heartless ones are taking the wrong attitude by burning the buses and putting at risk passengers and the driver."

Endemic student rioting has brought parts of Santiago to a standstill. Violent protests in June led to nearly 500 arrests, while police said 36 of its officers were injured.

Despite the continuing economic costs of the unrest and Pinera's rising unpopularity, key demands of the students' representatives remain unmet.

Most of the government-run schools have been criticized for the poor quality of education, while private universities have been singled out for both poor quality of education and restricted access. Banks have been criticized for fixing high interest rates for student loans.

Meanwhile, academic leaders are critical of Pinera and want a constructive dialogue between the government and students but many are afraid to speak out.

Pinera's response has been to reject calls for structural change in the education system and announce instead scholarships and soft loans. The program is said to be worth $1 billion but critics say the subsidy plan is poorly conceived and doesn't go far enough in solving the problem.