MONTEVIDEO (Reuters) - Uruguayans take to the polls on Sunday in primary elections ahead of October's presidential race, in which the left-wing opposition is seen edging ahead according to opinion polls with voters concerned about rising inequality and public safety. 

Polls show voters cooling on the center-right coalition of President Luis Lacalle Pou, despite its successful steering of the farming economy of 3.4 million people through the COVID-19 pandemic and the economic setbacks following the war in Ukraine.

Lacalle Pou, 50, has struggled to back up a pledge to tackle drug crime which is hurting Uruguay's reputation as a beacon of stability in turbulent South America. A perceived weakness of the welfare state and rising corruption has also hurt his party.

That has seen the center-left Broad Front coalition, which ruled from 2004 to 2015, edge ahead of the main center-right parties, latest opinion polls showed.

Uruguayan pollster Cifra predicts the Broad Front getting 47% support in May, some 15 points ahead of Lacalle Pou's National Party, the main force within the ruling coalition. The wider conservative bloc combined, though, would get around 43%.

Around 10% remain undecided suggesting that October's presidential election will be tight.

Whoever wins in general elections scheduled for Oct. 27, or more likely in a November runoff, will need to bring down high homicide rates, improve the social safety net, balance trade with major partner China and keep on track an economy that is expected to grow nearly 4% this year.

Lacalle Pou remains popular but his cabinet has been rocked by accusations of political espionage and corruption. He himself cannot run for immediate re-election.

Lacalle Pou narrowly won election in 2019 by forging a "multicolor coalition" including the centrist Colorado Party which his handpicked successor, Alvaro Delgado, plans to replicate. 

Delgado has pitched himself as the continuity candidate, having served as cabinet chief to the president, and is widely expected to secure the National Party nomination, polls show.

Several presidential hopefuls for the smaller Colorado Party have said they would unite behind the National Party nominee to prevent the left from returning to power.

The most contested leadership race is within the Broad Front opposition between two leftist city mayors.

Yamandú Orsi, mayor of Uruguay's second largest region and a former teacher, is expected to beat Carolina Cosse, mayor of the capital Montevideo where almost half of the population live. Orsi's experience and public endorsement from former president José Mujica, an icon of the Latin American left, meant he was better placed to win the presidential nomination, analysts said. 

"Uruguay today is an insecure and unequal country," Orsi told Reuters ahead of the primary vote, pledging "a modern left" that will reverse damaging rates of "poverty and destitution". 

Polls open at 8am local time (1100 GMT) and close at 7.30pm, with first exit polls expected around 9pm.

(Reporting by Lucinda Elliott; Editing by Adam Jourdan)

By Lucinda Elliott