Venezuelans have gone to the polls in parliamentary elections that are seen as a crucial test of support for Hugo Chavez, the Venezuelan president, ahead of a presidential ballot in 2012.
The focus of Sunday's election is on whether the opposition can garner more than a third of the 165 seats up for grabs, to grant them legislative power in the assembly.
Results were expected late on Sunday night or early Monday morning local time, but they have been delayed, fuelling accusations from the opposition that the government is too afraid to make an announcement.
The opposition has mounted a determined challenge to try to break Chavez's monopoly of power in the National Assembly for the first time in his nearly 12 year presidency.
Lucia Newman, Al Jazeera's correspondent in Caracas, the Venezuelan capital, said voter turnout has been huge.
"Chavez says he expects a turnout of up to 70 per cent of the 17 million people who are eligible to vote," she said.
"The opposition, united for the first time, hope to be able to put a break on the socialist reforms [introduced by Chavez].
"Whatever the outcome they [the opposition] will now have an institutional voice in this country, where each side has come to see the other as the enemy," she said.
Margarita Lopez Maya, an opposition candidate, told Al Jazeera she stopped supporting Chavez because he turned away from democracy.
"After his re-election in 2006 he changed from a political project of participative democracy into what he calls a socialist model for the 21 century," she said.
"That is more of a personality status and a totalitarian model. We are trying to build a non-polarised alternative for Venezuelans.
"Polarisation is a government strategy. The middle ground tends to sway towards Chavez because they don't want to go back to the past, but they are disgusted with the totalitarian trend. Their problems are not being resolved."
Chavez has had near total control since opposition parties boycotted the last legislative elections in 2005, citing concerns about possible irregularities.
If Chavez's opponents manage to deny him at least a two-thirds majority this time, they would have more clout in trying to put a check on his sweeping powers.
Decline in popularity
Polls suggest Chavez remains the most popular politician in Venezuela, yet surveys have also shown a decline in support for him in the past two years as disenchantment has grown over problems including high levels of crime, poorly administered public services and inflation now at about 30 per cent.
"We want a total change,'' Dieter Jaaniorg, a voter at a polling station in Caracas, said.
He said he is fed up with crime, a bad economy and an authoritarian government.
Cristian, his younger brother, said they see it as a last chance for the opposition to show it can stand up to Chavez.
"If we don't win today, it's straight to communism,'' he said.
Chavez is hailed by supporters as a champion of Venezuela's poor communities. But he is denounced by critics as a dictator.
His popularity is in the 40-50 per cent range - well below his highs in previous years. But that is probably enough to ensure that his party retains a majority.
"The opposition [is] very confident this time but they do not understand how the people feel," Carlos Cristiani, a Caracas resident, said.
"Chavez has problems, that's clear, but nobody wants these other [opposition] people. They will be very disappointed."
Initial results are expected about 02:30GMT on Monday.