Meanwhile, a number of countries said they would not recognize the election results.
His closest challenger, Henri Falcon, came in second with 21.2 percent, while Javier Bertucci was third with 10 percent.
In response, many opposition leaders called for an election boycott. As we went to press state television had not announced its results.
Accomplishing that should be the focus for global policymakers and Maduro's domestic opponents in the coming weeks and months.
But he showed no sign of replaying Sunday's vote. "We do not recognize this electoral process as valid", he told local media.
He also slammed Falcon, who like him was an acolyte of the late President Hugo Chavez. "A direct military invasion by the U.S. and its allies is also not out of the question", Pshenichnikov said.
Electoral authorities say turnout is projected to reach 48 per cent. "A big democratic fiesta is taking place!"
Filmmakers protest in solidarity with Palestine at Cannes
Well, this year Kristen put her money where her mouth is and literally kicked off her heels in front of the world's media. It's just like you simply can not ask me to do something that you are not asking him.
Falcon said fresh elections could be held in November or December, when they are traditionally contested, but they were moved up this year by the country's all-powerful and pro-government Constituent Assembly, catching the divided and weakened opposition off-guard.
Falcon promised to dollarize the economy, return companies expropriated by Chavez and allow humanitarian aid, something the president rejects.
A woman waiting outside a polling station in a Caracas slum, La Vega, said she worked for a government agency and feared losing her job if she did not vote and report afterward at the Red Spot. They underestimated me. Never before has a presidential candidate taken 68 percent of the popular vote.
Opinion polls say the overwhelming majority of Venezuelans distrust the electoral council.
Venezuela's populist leader Nicolas Maduro won a new six-year term on Sunday, but his main rivals disavowed the election alleging massive irregularities in a process critics decried as a farce propping up a dictatorship.
Opposition parties had warned in advance they feared the vote would be rigged in Maduro's favour.
Maduro, setting an example for government supporters who he called on to vote early, cast his ballot in Caracas shortly after fireworks and loud speakers blasting a military hymn roused Venezuelans from sleep around 5 a.m.
A coalition of 14 nations from throughout the Americas, including Brazil, Mexico and Colombia announced they would not recognise the result and pledged to ramp up diplomatic and economic pressure on Venezuela.
Opposition leader Omar Barboza said Monday that the Broad Front and the United Democratic Roundtable will push for a "free, transparent" election with worldwide observers in the last trimester of 2018. "I'm going to stubbornly and obsessively insist in dialogue for peace", he said.