A retired right-wing general promising to stamp out spiralling crime is favoured to win power in Guatemalan elections on Sunday, stirring up memories of the country's troubled years of military rule.

Supporters of the silver-haired Otto Perez, 60, believe he is the best candidate to tackle lawlessness and violence in the coffee- and sugar-exporting country, which has one of the highest murder rates in the Americas.

Although some fret about Perez's military past and his role in a 36-year civil war, polls ahead of the presidential vote showed him well ahead of his centrist rival Manuel Baldizon, a businessman with a message to help the elderly and the poor.

Both Perez and Baldizon, 41, say they will boost security spending but Perez has made a promise of a mano dura, or firm hand against crime, his campaign slogan.

I'm voting for General Otto Perez Molina because he's an ex-military man, said Jose Efrain Castillo, 73, a school bus driver who believes the former general has a better chance of cutting the murder rate than Baldizon.

Polling booths closed in Guatemala at 6 p.m. local time (midnight British time) and preliminary results are due shortly.

Voters at a shopping centre in an upmarket neighbourhood of Guatemala City said jobs and poverty are also pressing concerns in a country where more than half the population works informally or is underemployed.

Perez says he will promote tourism and foreign investment while Baldizon says he will make businesses pay employees bigger bonuses and give away fertilizer to help small farmers.

Perez has pledged to cut the murder rate by half and expand the army and police force to fight incursions by brutal drug cartels from neighbouring Mexico, as well as tackle the violent street gangs that wreak havoc in towns and cities.

But it is not clear where extra funds would come from, given Guatemala has one of Latin America's lowest tax revenues for the size of the economy.

SPECTER OF WAR

Perez won 36 percent of the vote in a first round of voting in September, compared to Baldizon's 23 percent, but his military past may weigh more in the rural areas which suffered most during the 1960-1996 civil war. About a quarter of a million people were killed or disappeared.

Baldizon, who defected from the ruling National Unity Party in 2008 to found his own Renewed Democratic Liberty party (Lider), has won support from many who lost family members during the war.

I'm not on the side of the military, said Alvaro Hernandez, 46, a photographer who said his wife is from Nebaj in the western highlands where Perez was stationed for part of the war and it is alleged his troops committed abuses.

Perez, who could become the first military man at Guatemala's helm since the return to democracy in 1986, has never been charged and dismisses the accusations.

I can tell you it's totally false, he told Reuters on Saturday. He was long seen by U.S. officials as a progressive officer inside the army and has said he will allow investigations into rights abuses during the conflict.

A U.N.-backed Truth Commission found the vast majority of war atrocities were committed by the military. Perez responds to questions about his own role in the war with a reminder that he signed the peace accords in 1996.

But analysts say not enough progress has been made in implementing the accords and that the elections come at a crucial point in the country's young democracy.

Guatemala is a very unequal society, said Javier Oliva, a political scientist at the National Autonomous University of Mexico (UNAM). And there is not great faith in democracy.

A 2011 survey by Latinobarometro, a Chile-based pollster, showed only 36 percent of Guatemalans felt democracy was the best form of government, the lowest rate in Latin America.