Students throw stones at a riot police vehicle, which was set alight by a molotov cocktail, during an anti-government rally to demand changes in the public state education system, in Valparaiso, about 120km northwest of Santiago.

Santiago - Mass student protests against the government of Chilean President Sebastian Pinera left 396 people arrested and injured 55 police officers and 23 civilians, the authorities said on Wednesday.

Tens of thousands of people gathered across the country on Tuesday to demand free, good-quality public education. This was the largest protest in Chile since the end in 1990 of the military dictatorship led by Augusto Pinochet.

Around 100 000 people gathered in Santiago alone, where some masked people clashed with police and vandalised private property. The government complained that these were violent demonstrators, while student leaders denied any of their protesters had committed criminal acts.

Last week a similar protest left 874 people arrested and 90 police officers injured.

The Chilean government planned to make an updated proposal to students on Wednesday, and called for negotiations.

In Chile, most school education and all universities require monthly fees. Student protests started three months ago and have already led to a change of minister.

The ongoing protests have eroded Pinera's approval rating, which sank to 26 per cent according to an opinion poll published last week, the worst of any Chilean president since 1990. - Sapa-dpa