(Recasts throughout with details from the prosecutor's request, reaction from Humala)
By Mitra Taj
LIMA, July 11 (Reuters) - A prosecutor in Peru is seeking up to 18 months in jail for former president Ollanta Humala and his wife to keep them from fleeing the country while money laundering charges are prepared against them, according to a request made public on Tuesday.
Prosecutor German Juarez, in the attorney general's office, said in a written request he had evidence that would prove in court that the couple took illegally obtained money from Brazilian construction company Odebrecht SA and the late Venezuelan president Hugo Chavez that was used to bankroll Humala's campaigns and for personal gain.
Humala denied any wrongdoing and called the request "surprising and abusive."
"We're complying with all of the prosecutor's orders. We've been collaborating with the investigation because we have the biggest stake in this being cleared up," Humala told reporters outside his home in Lima, where he spoke beside his wife and the co-founder of his political party, Nadine Heredia.
A hearing is scheduled for Wednesday and, if Judge Richard Concepcion approves Juarez' request, Humala would become the second former Peruvian leader sought for arrest since Odebrecht acknowledged publicly last year that it bribed officials across Latin America over a decade-long period.
Concepcion ordered former president Alejandro Toledo to be jailed for up to 18 months in February before a trial over allegations he took $20 million in bribes from Odebrecht. Toledo, believed to be in the United States, denies wrongdoing and has refused to turn himself in.
In Peru, the Odebrecht scandal has so far mostly tarnished the reputations of left-leaning Humala and centrist Toledo - allowing their right-wing critics to portray them as hypocrites for railing against graft in the government of their predecessor, former autocratic president Alberto Fujimori.
Fujimori is serving a 25-year prison sentence for convictions that include human rights violations and corruption.
Juarez said two of Odebrecht's former executives have testified that they arranged to send $3 million for Humala's 2011 campaign on orders from the Workers Party of Brazil. The money was the product of corruption, Juarez said.
Juarez also alleged that Humala's 2006 campaign was financed with money that Chavez stole from Venezuela's treasury.
Humala ran an unsuccessful presidential bid in 2006 as an ally of Chavez before winning the 2011 election after recasting himself as a more moderate leftist in the style of Brazil's former president Luiz Inacio Lula da Silva, who founded the Workers Party. (Reporting by Mitra Taj; Editing by Cynthia Osterman, Matthew Lewis and Paul Tait)