Conservative supermarket magnate Ricardo Martinelli won Panama's presidential elections in a landslide Sunday, taking office as the Central American nation carries out an ambitious project to expand the Panama Canal.

Martinelli, of the opposition Alliance for Change, had 61 percent of the votes against 37 percent for ruling party candidate Balbina Herrera, Panama's Electoral Tribunal reported with 63 percent of the votes counted.

Tribunal President Erasmo Pinilla called Martinelli, 57, the "indisputable winner" and said he had telephoned the candidate to inform him of his victory.

Martinelli, who owns Panama's largest supermarket chain, said he would work for a national unity government because "that is what the country is counting on."

"Tomorrow we will all be Panamamians and we will change this country so that it has a good health system, good education, good transportation and good security," he said.

Herrara, a 54-year-old former housing minister, still hadn't comment on the election results. Former President Guillermo Endara was a distant third in voting.

The winner, whose term ends in 2014, will have to guide Panama through the world economic crisis and the $5.25 billion expansion of the canal to increase its capacity and accommodate larger ships.

Both Martinelli and Herrera supported the canal expansion, but recent world economic woes have generated uncertainty over the project, which is receiving $2.3 billion in international financing.

The canal project, which was approved in a 2006 referendum, is expected to create about 5,000 direct jobs in the small Central American nation between 2010 and 2011, when construction is at its peak, according to authorities.

Martinelli has promised to push the project forward.

Herrera had promised to spread the capital's wealth to the rest of the country.

Panama's economy grew by an annual average of 8.7 percent over the past five years, and unemployment fell from 12 percent to 5.6 percent. The growth was fueled by foreign and state investment by the outgoing government of President Martin Torrijos. Growth this year is projected to be 3-4 percent.

Panamanians also elected a vice president, members of Congress, mayors and other local officials. More than 2.2 million people were eligible to vote.