But with inflation so crippling, many shoppers at those stores said the inconvenience was worth it.

“It’s an enormous help,” said Ana Lozano, 62, a retiree who takes in ironing to supplement her pension, who was waiting outside the Santa Rosalía grocery. “That’s why there’s such a long line.”

The government appears keenly aware of the twin threats of shortages and inflation as it prepares for the October election in which Mr. Chávez is seeking a new six-year term. The price controls have been defended in government advertisements and accompanied by repeated threats from Mr. Chávez to nationalize any company that cannot keep its products on the market.

Vice President Elías Jaua has warned of a media campaign to frighten Venezuelans into hoarding, which would provoke artificial shortages. Government advertisements urge consumers not to succumb to panic buying, using a proverbial admonition: Bread for today is hunger for tomorrow.

Francisco Rodríguez, an economist with Bank of America Merrill Lynch who studies the Venezuelan economy, said the government might score some political points with the new round of price controls. But over time, he argued, they will spell trouble for the economy.

“In the medium to long term, this is going to be a disaster,” Mr. Rodriguez said.

The price controls also mean that products missing from store shelves usually show up on the black market at much higher prices, a source of outrage for many. For government supporters, that is proof of speculation. Others say it is the consequence of a misguided policy.

Emilio Ortiz, 52, a shop owner, said he could buy sugar and powdered milk from his distributors only once last year. He gets cooking oil once a month, but only about half of what he requests. He also said that profits were so low on controlled products that he must raise other prices to compensate.

One of his customers asked if the store had Harina Pan, which is considered the quintessential local brand of flour to use in making arepas, the signature corn cakes that are a staple of the Venezuelan diet.