Dardo Chiesa, head of Argentina's Rural Confederation (CRA), said the company, whose founders are mired in a corruption scandal that threatens to topple Brazil's president, bought Argentine companies over a decade "at exorbitant prices to compete unfairly."

JBS said in an e-mailed statement there were no irregularities in its businesses in Argentina or in any country outside of Brazil.

Chiesa said he was scheduled to speak before Congress next week and would reveal his suspicions that JBS paid bribes in order to be favoured in export quotas managed by former President Cristina Fernandez's government. He said he did not have any proof of bribes.

"We are going to gather information first but there is information we want to investigate that they won't give to CRA... Either a congressional committee takes it or it goes to a prosecutor," he said.

JBS bought five meatpackers in Argentina, several of which have since shut down.

"Colcar was worth $3 million (2.34 million pounds), they paid $15 million. Venado Tuerto was worth $6 (million) and they paid $27 (million)," Chiesa said. Other companies JBS bought in Argentina were Swift Rosario, Frigorifico Pontevedra and Frigorifico San Jose.

Venado Tuerto and Pontevedra were acquired in competitive public auctions. SwiftArgentina, including the Rosario and San Jose plants, and Colcar were purchased at market price, JBS said.

Argentina under President Mauricio Macri has been trying to recover its standing as a top global beef exporter that was lost during the Fernandez government.

JBS said over the past decade its operations had been affected by political-economic conditions in Argentina, resulting in changes in production volume and the closure of some units.

JBS grew from a family-run butcher to the world's top beef company with operations in the United States and Australia thanks to financing from Brazil's state development bank BNDES.

Joesley Batista resigned last week as chairman after pressure from BNDES.

(Writing by Caroline Stauffer; Editing by David Gregorio and Cynthia Osterman)

By Maximiliano Rizzi