Toledo had 23 percent support, compared with 26 percent a week ago, according to a survey by the Lima-based group that was published in El Comercio newspaper today. Support for Keiko Fujimori, a congresswoman and daughter of jailed former President Alberto Fujimori, was unchanged from a week ago at 19 percent.
Humala, a former army lieutenant and ally of Venezuelan President Hugo Chavez, rose two percentage points to 17 percent, Ipsos Apoyo said. Humala, 48, favors more state control of the economy and natural resources.
According to the Ipsos Apoyo poll, Former Finance Minister Pedro Pablo Kuczynski had 14 percent support, compared with 9 percent a week ago, and former Lima Mayor Luis Castaneda fell 3 percentage points to 14 percent.
Support for Humala and Kuczynski, 73, is growing in Lima and other urban areas where they previously lagged behind the other main candidates, the poll shows.
The poll of 2,000 people from March 12 to 18 had a margin of error of 2.2 percentage points.
The poll included covered 5 of the 10 candidates running for the presidency. The first round of voting is scheduled for April 10. A second round will be held on June 5 if no candidate wins more than 50 percent of the first-round vote.
Toledo, 64, would defeat all the main candidates but Castaneda in a hypothetical run-off vote, according to Ipsos Apoyo.
To contact the reporter on this story: John Quigley in Lima at email@example.com.