Venezuelan President Hugo Chavez' party scored a string of victories in key local polls, but in a blow to his socialist revolution the opposition won some major power centres, results showed.

The results shake up the political landscape of the Opec nation, reducing the broad dominance of the fiercely anti-liberal Chavez and his party.

"The symbols won by the opposition are more than expected: they won the capital and states representing the economic and political heart of the country," said Luis Vicente Leon from Datanalisis.

Some 45 percent of the population will now be governed by policitians from the opposition, who won in states representing around 70 percent of national economic activity.

But Chavez said on Monday that the opposition had suffered a "new, big defeat."

"They continue overestimating what happened as a victory. That's crazy. We gave them a new, big defeat," Chavez said in a news conference with foreign journalists late on Monday.

The elections had been seen as a test for Chavez and his drive for nationalisation and social projects after an aggressive campaign drive, and amid growing discontent over escalating crime, corruption and inflation.

Candidates from Chavez's socialist party won 17 states out of 22 in the vote which came almost 10 years after he was first elected. They also won back three states previously held by dissidents from his party.

If "we're applying scientific analysis, the popular revolutionary victory continues growing," Chavez said.

But Chavez, a friend to Iran, Russia and Cuba's Fidel Castro, lost ground in his expected plan to seek support to abolish term limits to try to win a third six-year term in 2012.

And he faces new challenges in dealing with the opposition.

Chavez "will have to negotiate with them. He can't turn his back on them and that's excellent for democratisation in Venezuela," Leon said.

Chavez criss-crossed the oil-rich South American country campaigning for his party's candidates, one year after his defeat in a referendum on extending his authority.

Opposition groups meanwhile joined together to increase their chances for victory, running single candidates in a majority of states and municipalities to block Chavez's bid to extend his "21st century socialism".

Famous for his fiery language, 54-year-old Chavez had threatened to imprison opponents, or even send tanks onto the streets if his party lost in Carabobo.

Meanwhile, a dissident candidate in Chavez's home state of Barinas on Monday disputed the the polls there, which gave the hotly-contested governorship to Chavez's older brother, Adan.

About 300 candidates, mainly from the opposition, were prevented from running in Sunday's vote due to corruption allegations.

A record of more than 65 percent of 17 million eligible voters turned out to vote for governors, mayors and heads of regional councils.

AFP