Venezuela president Hugo Chávez. Photograph: Thomas Coex/AFP

President Hugo Chávez faces an important test of his self-styled socialist revolution on Sunday when Venezuelans vote in regional and local elections after a tumultuous election campaign.

Opinion polls suggest a resurgent opposition could win control of key states and cities and rein in the forceful president on the eve of his 10th anniversary in power.

Discontent over violent crime, inflation and poor public services threatens to topple government candidates and trip up Chávez's ambition to turn South America's energy giant into a socialist state.

With government revenues tumbling along with oil prices, the president has cast the election as an existential battle to protect the revolution from traitorous "little Yankees" and criminals who take orders from Washington.

"If I am to continue governing Venezuela, it will depend on what happens [on Sunday]. Make no mistake, Chávez's political destiny is in play here," he said this week.

Opposition leaders said the vote was a chance to rebuff an authoritarian megalomaniac whose corrupt and incompetent rule frittered a historic oil windfall.

"It is not a choice between capitalism and socialism, that's a lie. Here the choice is between efficiency and inefficiency," said Carlos Ocariz, the opposition candidate for Sucre, an impoverished municipality in Caracas which opinion polls suggest has swung away from Chávez.

Some 22 of 23 state governorships are up for grabs as are 328 of 335 municipalities. An opposition boycott helped give the president's allies an almost clean sweep in the previous regional elections in 2004, making it almost certain he will lose some governors and mayors on Sunday.

If losses are minimal analysts expect Chávez to declare victory and push for a constitutional referendum to abolish term limits, allowing him to stay in power for as long as he wins elections.

"A lot is at stake. Erosion of support is natural after 10 years so if Chávez does well on Sunday it shows he must be doing something right," said Steve Ellner, a political scientist at Venezuela's University of the East.

Chávez's personal approval ratings remain over 50%, a tribute to his charisma and investment in free health clinics and subsidised grocery stores. But many of his own supporters are fed up with rampant murder rates, potholed roads, uncollected rubbish and inflation of 35%, the region's highest.

"I voted for him before but not again. He's giving our resources away overseas and doing nothing here. Look at the state of this place," said Neria Fernandez, 64, a housewife gesturing to mounds of rubbish in Petare, a Caracas slum.

Polls suggest the government could lose in six to nine states, including some of the most populous and economically important such as Carabobo, Miranda and Zulia.

Chávez may also lose Barinas, his home state where his brother Adan is running to succeed their father as governor. Allegations of corruption and nepotism have split government supporters.

The opposition has complained of intimidation and manipulation. Several big name candidates were banned from running over corruption accusations and others who appear poised to win have been threatened with jail. The president threatened to mobilise tanks in Carabobo if voters rejected his candidate, a shock-jock TV host called Mario Silva.

The opposition has also alleged abuse of state resources. State TV runs non-stop propaganda for Chávez candidates and municipal buses ferry people to government rallies. Government-backed communal councils have distributed thousands of fridges, cookers, washing machines, fans, mattresses and beds.

Government supporters see little wrong with a petro-state helping the poor in that way. "Thanks to the president Venezuela is different," said Donnala Perez, 53, braving rain at a government rally.
"We have a lot of things because of him. Before the poor weren't able to study, now we have universities. We have clinics, doctors who come to our homes. We are living in a happy time."