CARACAS, Venezuela (AP) - Former Venezuelan president Hugo Chavez's hand-picked successor Nicolas Maduro won a razor-thin victory in Sunday's special presidential election, edging the opposition's leader by only about 300,000 votes, electoral officials announced.

Mr Maduro's stunningly close victory over Mr Henrique Capriles came after a campaign in which the winner promised to carry on Mr Chavez's self-proclaimed socialist revolution while the challenger's main message was that Mr Chavez's regime put Venezuela on the road to ruin.

Mr Maduro, acting president since Mr Chavez's death last month, held a double-digit advantage just two weeks ago, but electoral officials said he got just 50.7 per cent of the votes to 49.1 per cent for Mr Capriles.

Chavistas set off fireworks and blasted car horns as they cruised downtown Caracas in jubilation.

There was no immediate word from the Capriles camp but Mr Maduro addressed a crowd from the presidential palace. He called his victory further proof that Mr Chavez "continues to be invincible, that he continues to win battles." He said that Mr Capriles had called him before the results were announced to suggest a "pact" and that Mr Maduro refused. There was no immediate word from Mr Capriles.

Mr Maduro, a longtime foreign minister to Mr Chavez, rode a wave of sympathy for the charismatic leader to victory, pinning his hopes on the immense loyalty for his boss among millions of poor beneficiaries of government largesse and the powerful state apparatus that Mr Chavez skillfully consolidated.

Mr Capriles' main campaign weapon was to simply emphasise "the incompetence of the state" in handling the world's largest oil reserves.

Millions of Venezuelans were lifted out of poverty under Mr Chavez, but many also believe his government not only squandered, but plundered, much of the US$1 trillion (S$1.23 trillion) in oil revenues during his tenure.

Venezuelans are afflicted by chronic power outages, crumbling infrastructure, unfinished public works projects, double-digit inflation, food and medicine shortages, and rampant crime - one of the world's highest homicide and kidnapping rates - that the opposition said worsened after Mr Chavez succumbed on March 5 to cancer.

That discontent was thick across the nation.

"We can't continue to believe in messiahs," said Mr Jose Romero, a 48-year-old industrial engineer who voted for Capriles in the central city of Valencia.

"This country has learned a lot and today we know that one person can't fix everything."

Turnout was 78 per cent, down from just over 80 per cent in the October election that Mr Chavez won by a nearly 11-point margin.