Voters in Panama are set to go to the polls on Sunday to pick the country's next president, after a campaign that revealed few major policy differences among the top candidates.

The campaign has gone down to the wire, with polls giving any of the three leading contenders a reasonable shot at victory.

Panamanians will choose among ruling party candidate Jose Domingo Arias, opposition politician Juan Carlos Navarro and Vice President Juan Carlos Varela - a slate of options that leaves many people here shrugging their shoulders.

"Whoever wins, I still have to go to work on Monday," said Manuel Dominguez, a sidewalk merchant who makes his living selling batteries and TV remotes in the heart of Panama City, the capital.

Polls open across the country at 7:00am (1300 GMT), with the first returns expected to trickle in about three hours later.

The winner of the seven-candidate race will take office July 1.

Voters will bid farewell to President Ricardo Martinelli, who, after a five-year term, is constitutionally barred from running for a consecutive second.

Arias, 50, Panama's former housing minister, is a businessman who made his fortune manufacturing ladies' undergarments.

Representing the Democratic Change party he is the pick of incumbent President Ricardo Martinelli, whose wife, Marta Linares, is on the ticket as Arias's running mate.

Navarro, 52, of the center-left Democratic Revolutionary party, was formerly mayor of Panama City. He has vowed to crack down on crime and to do more to protect the environment.

Trailing the top two by a handful of percentage points is Varela, 50, a rum manufacturer who is Martinelli's current vice president, but now is seen as his political enemy.

The two had a falling out after Martinelli dismissed Varela as his foreign minister in 2011, opening a political wound that has yet to heal.

Some 2.5 million people out of a population of 3.8 million are eligible to vote in the election, with voters across the country also tasked with electing dozens of mayors and members of Congress.

A victor is guaranteed to be declared in the presidential vote, since a simple majority will win the election.

Lawyer and political analyst Ebrahim Asvat, said that whatever the outcome of the vote, the country's course for the next quarter century already has been laid out.

Panama will continue to focus, he said, on free market policies that maximise economic expansion - the path forged by Martinelli.

"Panama has made an extraordinary effort to open up its economy, exercise fiscal discipline and none of the candidates is going to veer from that path," Asvat said.

The massive project to widen the Panama Canal was also undertaken on Martinelli's watch, and while the effort has been bedeviled by delays and cost overruns, in the long run it is likely to be seen as enhancing his legacy, and benefiting the country.

Martinelli leaves office with a 67 percent approval rating, and Panamanians seem inclined to vote for whoever of the three candidates is most inclined to stay the course.

Source: AFP