Peru's opposition Popular Force party, which has a majority in Congress, asked for Finance Minister Alfredo Thorne's resignation on Friday, the party's
spokesman Luis Galarreta told a news conference.
Lawmaker Mauricio Mulder said Congress would censure Thorne if he did not resign. Thorne denied wrongdoing but told lawmakers he needed their support to remain in his job.
Thorne was called to Congress over a recording in which he appears to ask the comptroller's office to approve a $520 million airport contract in exchange for a bigger budget.
Peru's President Pedro Pablo Kuczynski said earlier he had a plan in place in case Thorne was forced to resign over accusations he improperly tried to influence an airport contract.
"We have a replacement plan in case the worst happens, but I don't think that will happen," Kuczynski said in comments broadcast on state television. He did not give details of the plan.
The government withdrew the 40-year operating contract for an airport near Cusco on May 22 after the comptroller released an official report pointing to irregularities in the contract.
Earlier this month, local television station Panamericana released the recording of Thorne, a former J.P. Morgan Chase executive, appearing to ask comptroller Edgar Alarcon to greenlight the contract.
Thorne has denied offering a quid pro quo and said there were gaps in the released recording.
The conversation took place after Alarcon had publicly expressed doubts about the contract but before the comptroller released the formal report.
"It would never occur to me to condition additional funds for the comptroller's budget on obtaining a favorable report on any investment project," Thorne told Congress on Friday.
Kuczynski, a business-friendly former investment banker, defeated populist Keiko Fujimori, the daughter of jailed former autocratic President Alberto Fujimori, in a razor-thin election last year. But her Popular Force party controls congress with 72 of 130 seats.