Ex-banker Pedro Pablo Kuczynski, of the Peruvians for Change (PPK) party, is leading Peru's presidential run-off.
Kuczynski, who was runner up in the first round vote in April, was leading on Sunday with 50.5 percent of the votes, Xinhua news agency cited polling firm Ipsos as reporting.
Keiko Fujimori of the Popular Force (FP) party, who won the first round, was trailing in second place with 49.5 percent of the votes, said Ipsos.
A difference of one to two points is considered a technical tie, due to the margin of error that polling firms consider in doing surveys.
Another polling firm, the GFK, also has the PPK candidate in the lead, with 50.9 percent, versus 49.1 percent for Fujimori, the 41-year-old daughter of former president Alberto Fujimori (1990-2000).
Fujimori is serving time in prison on corruption charges and human rights violations.
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More official figures were expected to be issued around 9.00 p.m. (local time) by Peru's National Office for Electoral Processes (ONPE).
Both candidates have so far been reserved in their reactions to the preliminary outcome in favour of the 77-year-old businessman who has held prior ministerial posts.
The ONPE said it would release official preliminary results after tabulating some 30 percent of votes cast nationwide.
Nearly 23 million registered voters were eligible to take part in Sunday's runoff.
The winner will succeed Peru's President Ollanta Humala on July 28, for a five-year term.
--IANS
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