Tight race in Panama

Polls opened Sunday morning local time, with most predictions showing the three top candidates within a few points of each other in the battle to lead Latin America's fastest growing economy. Panama is a banking and trading hub that links the Atlantic and Pacific Oceans.

Slightly ahead with a razor thin lead is former Housing Minister Jose Domingo Arias (above, second from right), the hand-picked candidate of outgoing president Ricardo Martinelli and his ruling Democratic Change (CD) party. He is closely followed by former Panama City mayor, Democratic Revolutionary Party (PRD) and moderate leftist candidate Juan Carlos Navarro (first left), and the center-right Vice President Juan Carlos Varela (third from left).

Panama's constitution bars Martinelli from seeking a consecutive re-election, but there are fears Arias will act as his proxy should he win, allowing the supermarket billionaire and soon-to-be former president indirect hold over the country.

Martinelli, who saw popularity rates of around 65 per cent at the end of 2013, has warned that Panama's record growth and low unemployment could be jeopardized should his opponents win.

Adding to the mix is Martinelli's decision to place his wife, First Lady Marta Linares, as Arias' running mate, despite her having no political experience. If Arias wins, it'll be the first time a ruling party is re-elected since the US overthrow of military strongman Manuel Noriega in 1989.

The campaign period has seen all three main candidates viciously attack each other.

Navarro has faced unsubstantiated claims of links to drug trafficking and Nicolas Maduro, the Venezuelan president who recently severed ties with Panama. He has promised to improve government transparency after President Martinelli faced corruption allegations over infrastructure contracts he awarded.

Varela, meanwhile, has defended himself over media leaks that he received payments from the daughter of a political friend convicted in the United States of money laundering.

The president of Panama's electoral tribunal has warned that the election results could be contested.

"Weakening the referee in the crucial moment of the electoral process marked by highly aggressive language serves no purpose than to commit fraud," Erasmo Pinilla said.

jr/jm (AP, Reuters)