BOGOTA - Whoever wins Colombia's presidency will face a divided congress and likely street protests, which will complicate efforts to carry out badly-needed fiscal and social reforms, analysts and politicians said.

Colombians vote on May 29 amid high polarization and grating inequality worsened by price rises, despite an incipient post-pandemic economic recovery.

Leftist Gustavo Petro, a former guerrilla and current senator, is leading his center-right rival Federico Gutierrez by about 10 points in opinion polls, though the contest looks set to go to a second round in June.

Petro is backed by many poor and working class Colombians but viewed with suspicion by investors, who say his plans to halt new oil development and redistribute pension funds would put economic stability at risk.

Gutierrez - known as Fico - has more of the kind of conventional centrist polices that investors prefer. He has proposed anti-tax evasion measures, cuts to government operating costs, and a gradual $2.5 billion tax reform to help Colombia regain its debt investment grade.

But either candidate would take office with a congress split among a dozen parties and a $15 billion fiscal deficit, equivalent to about 6.2% of gross domestic product.

"The pluralist make-up of Congress obliges the president to reach consensus with parties that aren't on their side of the ideological spectrum," said Fedesarrollo thinktank director Luis Fernando Mejia.

"We don't see a candidate so far who would have more ability to generate that consensus, it would all depend on their leadership."

Among Petro's top proposals is a $13.5 billion tax legislation overhaul, which would tax the richest Colombians to fund social programs, and monthly payments of half the minimum wage - about $125 - to older people who do not have pensions.

"It's a bit of a reformulation of the role of the state in the economy," Petro economic adviser Luis Fernando Medina told students at a recent forum. "Our proposal is a fiscal consolidation on the income side and also more assertiveness on spending, more public investment."

Gutierrez, meanwhile, has floated proposals to eliminate pension subsidies for high-earners and formalize millions of jobs.

"It's a safe bet for investors and business people and that's no small thing in Colombia's current circumstances and in the context of Latin America," said Gutierrez campaign official Manuel Castro. "Fico defends business, he guarantees legal certainty to boost private and public investment."

Gutierrez is widely seen as an ideological successor to deeply unpopular President Ivan Duque, who is term-limited.

He is likely to face street protests similar to the sometimes violent demonstrations over the last three years, where protesters have demanded police reform, radical changes to student loan policies and more generous efforts to fight profound inequality.

Protests can pack a hefty economic punch - in 2021 road blockades halted exports of coffee and led major oil and coal producers to temporarily stop some production.

To try and stave them off, Gutierrez has taken pains to emphasize his plans for a basic income for 5 million people and salary increases.

Petro may initially face less risk of protests, but if he fails to show rapid results he could find himself grappling with discontent like leftist leaders in Peru and Chile.

Peru's Pedro Castillo, in power since July 2021, has survived two attempts to remove him from office, while Chile's Gabriel Boric has seen his approval ratings plummet in just two months.

"This is an issue which will affect a right-wing president just as much as a left-wing one, where the community, especially young people without opportunities, will keep protesting," said incoming center-right Radical Change senator Carlos Jimenez.

Independent candidate Rodolfo Hernandez, a businessman who is enjoying a late rise in polls that puts him just behind Gutierrez, has shared few details about his economic plans.

Known for his anti-corruption promises and whimsical social media presence, he is broadly seen as business-friendly.

"We think it would be unwise to discount late momentum from a populist outsider," said Ben Ramsey, head of economic studies for Latin America at JPMorgan.

About half of Colombians live in some form of poverty, a situation exacerbated by the coronavirus pandemic.

"The discontent is there and it will stay despite economic recovery... the labor market and other things are lagging, so Petro and Fico Gutierrez will eventually have to confront that," said Sun Capital analyst Juan Manuel Patino.

"The message from the region in general when you look at Peru and Chile is that you must make deals."

(Reporting by Nelson Bocanegra, Writing by Julia Symmes Cobb, Editing by Rosalba O'Brien)