Factbox: Panama's presidential candidates and their policies

PANAMA CITY (Reuters) - Panama will elect a new president on Sunday to succeed incumbent Juan Carlos Varela.

Here are the main candidates competing for a five-year term at the helm of Central America's fastest-growing economy.

LAURENTIO "NITO" CORTIZO, DEMOCRATIC REVOLUTIONARY PARTY (PRD)

Cortizo of the moderate left PRD is the front runner and has pledged to improve government services like water supply and healthcare without privatizing them.

Cortizo, 66, says he will make healthcare more accessible for the poor in particular, and combat medicine shortages by centralizing purchasing and distribution.

An April 13-15 survey by polling firm Stratmark Consultores gave Cortizo support of 49.8 percent of voters.

A former businessman who also worked for the Organization of American States in Washington, Cortizo was twice a member of Congress in 1994-2004, and its president in 2000-2001.

ROMULO ROUX, DEMOCRATIC CHANGE (CD)

Roux, from the center-right CD, has proposed constitutional reform to strengthen Panama's judiciary after a bribery scandal involving Brazil's Odebrecht construction company.

The lawyer is Cortizo's main challenger, polling support of 26.4 percent in the Stratmark poll.

He has proposed cutting bureaucracy and to make Panama's social security fund more transparent and sustainable.

Roux, 54, was foreign minister in 2012-2013, and previously chaired the board of the Panama Canal Authority.

He was endorsed last week by former President Ricardo Martinelli, who is awaiting trial in prison on charges he spied on politicians, unionists and journalists, but still enjoys popular support.

ROBERTO LOMBANA, INDEPENDENT

Lombana, 45, was a relative unknown until recently. He made substantial gains in the most recent poll, boosting his support to 10.5 percent from 0.8 percent in about two months.

Campaigning against the political establishment, Lombana, a lawyer, has pitched a smaller government to voters and zero tolerance on

OTHERS

Jose Isabel Blandon from Varela's Panamenista Party and other candidates, including the only female candidate, Ana Mathilde Gomez, are well behind in polls.

(Reporting by Stefanie Eschenbacher and Elida Moreno in Panama City; editing by Dave Graham and Cynthia Osterman)