At least three supermarkets in the popular ski resort were targeted, causing panic among local residents and tourists.
Dozens of people, many with their faces covered, broke into the supermarkets stealing electronics, toys and clothes.
The government blamed small criminal gangs but local authorities pinned the attacks on anarchist organisations.
![Looters in Bariloche](/6488793864887937.jpg)
Governor Alberto Weretilneck called for federal troops to restore order in Rio Negro, in the country's Patagonia region.
"With this type of action, these groups have been trying to paint a false picture of social and political collapse," the provincial authorities said in a statement.
The attacks took place in San Carlos de Bariloche, an Andean resort popular with tourists from other South American countries.
Local police said other shops and depots on the outskirts of the town were also targeted by looters. All shops closed after the thefts.
President Cristina Fernandez de Kirchner has been in constant communication with the province's governor, according to her spokesman Juan Manuel Abal Medina.
He said the Bariloche attacks were linked to the sabotage of power lines earlier on Thursday in the neighbouring province of Neuquen.