Venezuelan President Hugo Chavez called for calm as the country awaited preliminary official results of Sunday's election, dpa reported.
"Let's stay calm," Chavez said in a phone call with his campaign command as it held a press conference. "Let no one become desperate. (Election authorities) are doing their job in an impeccable fashion. Let's await the results with patience, with calm and, well, let's get ready to acknowledge the results whatever they may be."
The left-wing populist, who has ruled Venezuela since 1999, was seeking another six-year mandate in Sunday's election against unified opposition candidate Henrique Capriles.
Polls opened at 6 am and generally closed 12 hours later although some polling centres remained open for as long as there were people in line to vote.
Initial estimates put the turnout at close to 80 per cent, and there were long lines at polling stations with waits of up to three hours in some cases.
Exit polls were not permitted, and no time was set for the first preliminary official results, which could come late Sunday. Election authorities said results would be made public once the count reveals an irreversible trend.
Opinion polls ahead of the election indicated no clear frontrunner. Some gave Chavez a lead of up to 20 percentage points while others showed the two candidates so close that the differences were within the polls' margins of error and others gave former governor Capriles a statistically significant lead.
About 18.9 million Venezuelans were registered to vote electronically at almost 14,000 polling stations across the country.
Chavez, who remained hugely popular, particularly among Venezuela's poor, had said he wanted to win the election with 70 per cent of the vote.