(Updates with quotes from president in paragraphs 4-5)

By Brian Ellsworth and Daniel Wallis

CARACAS, Nov 19 (Reuters) - Venezuelan lawmakers granted President Nicolas Maduro yearlong decree powers on Tuesday that he says are essential to regulate the economy and stamp out corruption but adversaries view as a power grab.

Hundreds of supporters of the ruling Socialist Party cheered outside the National Assembly as the so-called Enabling Law was passed, while a recording of Maduro's late predecessor, Hugo Chavez, singing Venezuela's anthem rang out inside the hall.

The power to pass laws without congressional approval gives Maduro a political victory in the run-up to Dec. 8 municipal elections, although he still faces a severely distorted economy with embarrassing product shortages and inflation surging to nearly 55 percent.

"I want to thank the majority of patriotic and socialist lawmakers for approving this law that will let us advance, over the next 12 months, in defeating the economic war being waged against our people," Maduro said.

"Tonight has been a victory for the people! ... Who says the revolution is over?" he added, flanked by ministers, to applause from a crowd outside the Miraflores presidential palace.

The passage of the decree powers on Tuesday was widely expected and Chavez passed nearly 200 laws by decree during his time in office, including legislation that let him nationalize major oil projects and increase his influence in the Supreme Court.

Maduro, 50, who is staking his rule on preserving Chavez's leftist legacy, says he has already planned the first two laws he will decree - maybe as soon as Wednesday.

One is intended to limit businesses' profit margins to 15 percent to 30 percent as part of an "economic offensive" against price-gouging. Another would create a new state body to oversee dollar sales by Venezuela's currency control board.

Diosdado Cabello, the head of the National Assembly and a staunch supporter of the president, said lawmakers had fulfilled an order by the late Chavez when they backed the legislation.

"He told us to pass all the laws necessary to wring the necks of the speculators and money launderers," Cabello said.

Maduro's original justification for decree powers was to toughen a crackdown on corruption, drawing skepticism from critics who say he zealously targets opposition officials while turning a blind eye to the worst of state-linked graft.

"Why don't you punish people who have not complied with the (existing) laws? You want the Enabling Law to concentrate power," one opposition leader, Julio Borges, accused "Chavista" legislators during a charged debate ahead of the vote.