People wait to buy medicines at a drugstore in Caracas Thomson Reuters CARACAS (Reuters) - A government plan to combat Venezuela's food shortages by fingerprinting shoppers in grocery stores has sparked a backlash ranging from violent street protests to social media campaigns ridiculing the idea.

Shoppers have for more than a year struggled to find basic goods including cooking oil, powdered milk and corn flour as well as detergent, shampoo and diapers.

Apart from a short supply of dollars for imports, the shortages have been blamed on heavy subsidies that allow shoppers to stock up on staples and resell them in neighboring Colombia or on the local black market.

President Nicolas Maduro says the biometric system, to be introduced this year, will allow authorities to weed out smugglers, often seen in lines buying conspicuous amounts of goods that are in short supply.

"It's absurd. How does a fingerprinting machine help you? It's only more regulation," said Jose Briceno, a pastry chef who was once a fervent supporter of late socialist President Hugo Chavez but says his handpicked successor, Maduro, should resign.

"I've reached my limit," said Briceno, 39, adding that he has to go shopping nearly every day to find what he needs for his kitchen.

Demonstrators opposed to the fingerprinting scheme clashed this week with police in San Cristobal, a city near the border with Colombia where product shortages are among the worst in Venezuela.

Some Caracas residents banged pots and pans on Thursday night in a traditional display of anger although the issue looks unlikely to spark the kind of massive demonstrations that rocked Venezuela for three months this year.

"I wanted to strangle Maduro," Esperanza Diaz, a 54-year-old retired government worker, said of the plan. "We can't keep being abused," she added, speaking in front of half-empty shelves as she stocked up on rare sugar at a sprawling government-run Bicentenario supermarket in central Caracas.

'SCAN THIS'

Government supporters argue that while stores in this oil-rich South American nation used to be better supplied, the poor could ill-afford to stock up on many consumer items anyway. They blast what they call a pampered, out-of-touch elite for seeking to stir up trouble.

"I agree with the fingerprinting system because I see how smugglers are bleeding the country dry," said Ninoska Mazza, 40, a real estate agent waiting behind other shoppers at a Bicentenario meat counter.

Venezuelans used to dodging socialist regulations are already joking that "rent-a-fingers" will soon emerge to help duck around the system.

A Twitter campaign shows a hand flashing the middle finger with the hashtag #ScanThisFingerprint.

The government has in recent days scaled back the fingerprinting plan, saying it will be voluntary and only required for 23 basic goods. Some Venezuelans are skeptical the plan will even be implemented but others see a dark motive behind it.

"They want to control us," said Monica Betancour, 43, a dentist looking for turkey at a supermarket in posh eastern Caracas. "Whenever they announce a protest against this, I'll be there," she said.

(Reporting by Alexandra Ulmer; Editing by Brian Ellsworth, Kieran Murray and Tom Brown)