A pro-business candidate fighting for a place in Peru's presidential runoff urged election officials to resolve delays in the vote count, with her party saying the race could hinge on the uncounted ballots.

With nearly 87 percent of the votes counted from Sunday's election, nationalist candidate Ollanta Humala was ahead with 30.4 percent of the tally, followed by ex-President Alan Garcia with 24.6 percent and former Congresswoman Lourdes Flores with 23.4 percent.

Since no one candidate received 50 percent support, a runoff will be held in late May or early June between the two top vote-getters. With Humala assured of a spot in the runoff, the race has now focused on the fight for second place.

A complete tally was expected by Friday but final official results might not be known for another two weeks, officials said.

Flores told reporters Tuesday that some 7,300 vote-tally sheets had not yet been counted because of legal challenges or problems with data entry into the electoral authority's computers.

"That represents 1.5 million votes," she told reporters Tuesday night. "I do not know if those votes favor me or not. We only want the truth to come out."

Xavier Barron, spokesman for Flores' Popular Christian Party, said the election's outcome could hinge on those untabulated ballots and demanded that election officials speed up the counting.

"This is an irregularity that must be corrected," he said.

Carlos Loyola, chief of planning for the national election authority, said every vote would be counted in due course and called for patience.

Flores, 46, said she was also counting on results from overseas ballots to overtake Garcia.

Garcia, 56, whose 1985-1990 tenure was marked by economic disarray and a bloody insurgency, said he was convinced that as the vote count progresses the distance between him and Flores will increase.

Humala has tapped into a powerful vein of discontent among Peru's poor majority with a populist message inspired by the 1968-75 left-wing military dictatorship of Gen. Juan Velasco and Venezuelan President Hugo Chavez.

The 43-year-old former army lieutenant colonel promises heavy state intervention in Peru's free-market economy and to strip political power from a European-descended elite.