Chile’s government has ordered 10,000 troops onto the streets to restore order in towns stricken by Saturday's earthquake.
Police fired tear gas at looters at one supermarket that later caught fire in the badly hit central city of Concepcion.
The government is scrambling to provide aid to thousands of homeless people.
Chile President Michelle Bachelet said the devastation had brought about an emergency without parallel.
The government has raised the death toll to 711 from the 8.8 magnitude quake.
Harrowing scenes of destruction are emerging in isolated towns swamped by the giant waves that were triggered by one of the strongest earthquakes in a century.
With many people missing and some communities in the worst-hit central region of the South American country still largely cut off by mangled roads, President Bachelet said the death toll was certain to rise.
Surging waves ruined houses and smashed cars in fishing villages on the country's long Pacific coast.
About 350 people died in the town of Constitución alone, state TV quoted emergency officials as saying.
A night-time curfew went into effect in the Maule region and in the heavily damaged town of Concepcion last night, where hundreds of looters had ransacked stores for food and other goods.
Looting also broke out in parts of the capital, Santiago.
‘We don't have water or anything. No one has appeared with help and we need more police to keep order. There are many people here who are robbing,’ said a 78-year-old woman who identified herself as Ana in the badly hit city of Talca, 250km south of Santiago.
In Concepcion, angry survivors camping along roads took out their frustration on firefighters who were distributing drinking water in thermoses and tea kettles, damaging their vehicles.
The damage from the quake could cost up to €22 billion, equivalent to about 15% of Chile's Gross Domestic Product, said Eqecat, a firm that helps insurers model catastrophe risks.
Some economists predicted a deep impact on Chile's economy after the quake damaged its industrial and agricultural sectors in the worst-hit regions.
