Supporters say it could lift country out of poverty, but opponents point to potential for environment and rights abuses.
Nicaraguan President Daniel Ortega is on course to win a third consecutive term in a vote that the opposition called a farce.
The president of the Supreme Electoral Council, Roberto Rivas, said late on Sunday that Ortega had more than 71 percent of the votes with about a fifth of the ballots counted.
Ortega, who ran with his wife Rosario Murillo as his vice-presidential candidate, faced five other lesser-known candidates in an election that critics of the government had called unfairly tilted against the opposition.
Rivas said 65 percent of Nicaragua’s 3.8 million registered voters participated in the election. The opposition, which had urged people to boycott the election, disputed that, contending turnout was low.
The main opposition movement, the Broad Front for Democracy, said its checks indicated that “more than 70 percent” of voters did not cast ballots.
Emerging with her husband after casting their ballots shortly before the polls closed, Murillo called the vote “an exemplary, historic election”.
Al Jazeera’s Latin America Editor Lucia Newman, reporting from Managua, said Murillo was “widely seen as the power behind the presidency”.
“She is the person who normally addresses the Nicaraguan people everyday at midday, unlike President Ortega who is rarely seen and heard from. This will give her the legitimacy now to take over should anything happen to him,” she said.
“But this has led to widespread charges that the Ortegas are trying to install a family dynasty – something that the Nicaraguans fought so hard to get rid of when they overthrew Anastasio Somoza in 1979.”
Another bone of contention is the fact that international observers from the EU, the Organization of American States and even The Carter Center were not allowed to be here to oversee the polls, said Newman.
There were no vote counts yet for 92 congressional seats that were also contested on Sunday.
Ortega and his leftist Sandinista National Liberation Front have benefited from the Central American country’s steady economic growth and low levels of violence compared to neighbouring Honduras and El Salvador.
Many Nicaraguans also cite the first lady’s social programs as a major reason for the governing party’s popularity.
But critics accused Ortega and his allies of manipulating the political system to guarantee he stayed in power for a new five-year term by dominating all branches of government, allowing indefinite presidential re-election and delegitimising the only opposition force seen as capable of challenging him.
They said he wants to form a political dynasty together with his wife.
“I don’t think it’s worth voting and wasting time, because it’s already fixed,” said Glenda Bendana, an appliance sales executive in a Managua shopping mall.
“Here they have taken away not our right to vote, but to choose. Ortega wants to die in power and leave his wife to take his place.”
Eva Duarte Castillo, with a degree in marketing, was among those who went to the polls, though she did not say how she voted.
“I came to vote because it is not only my right as a citizen, it is also my duty. It is a responsibility and I exercised it. I’m happy,” she said at a polling station in the capital’s Altamira Managua neighborhood.
In July, Nicaragua’s Supreme Electoral Council effectively decimated the opposition by ousting almost all its members from congress – 28 active and alternate legislators from the Liberal Independent Party and the allied Sandinista Renovation Movement – for refusing to recognise Pedro Reyes as their leader.
Reyes was named head of the opposition by the Supreme Court but is seen by many as a tool of Ortega. The ousted legislators supported former opposition leader Eduardo Montealegre.
Many Nicaraguans believed the five other presidential candidates were not true opponents, but were placed on the ballot to make it seem that Ortega had legitimate competition.