Turkish riot police have fired tear gas at protesters who gathered outside a hospital after a teenage boy injured during last year's anti-government protests and left comatose, died.

Nearly 1,000 people staged a rally outside an Istanbul hospital on Tuesday in solidarity with 15-year-old Berkin Elvan, who was walking to buy bread when he was struck in the head by a tear gas canister during the unrest in the city in June.

The story of Elvan, who spent 269 days in a coma, gripped the nation and became a symbol of the heavy-handed tactics used by police to reign in the biggest demonstrations that Prime Minister Recep Tayyip Erdogan had faced since coming to power in 2003.

Police used tear gas and water cannon after several dozen protesters hurled stones at a police bus and stole helmets and shields, an AFP photographer said, adding that one demonstrator was injured.

Silent vigils were held in the cities of Izmir, Antalya and Eskisehir, where a large number of students boycotted their classes, according to local media.

The boy's mother Gulsum Elvan, speaking to reporters outside the Istanbul hospital, challenged Erdogan who had praised police "heroism" during the protests.

"It's not God who took my son away but Prime Minister Erdogan," she said.

President Abdullah Gul, who had called Elvan's family while he was in a coma, expressed his sadness at the boy's death. Gul urged everyone "to do everything to prevent this from happening again".

Human Rights Watch charged that police violence against demonstrators was an "endemic problem" in Turkey.

Protests last year started as a small environmentalist movement to save an Istanbul park from being razed, but snowballed into a nationwide wave of protests against Erdogan, who critics say had become increasingly authoritarian.

Elvan's death brought the toll from the unrest to at least eight, including a policeman.