BUENOS AIRES (Reuters) - Argentine soy farmers fear they will get shortchanged under a proposal they say would favor U.S. agricultural company Monsanto Co by forcing them to pay royalties on seeds grown on their own farms using the company’s genetically modified technology.

Trading information is displayed on a screen at the post where Monsanto Co. is traded on the floor of the New York Stock Exchange (NYSE) in New York City, U.S., August 25, 2016. REUTERS/Brendan McDermid

Farmers in Argentina’s Pampas grains belt say they should have to pay only once, or maybe twice, for seeds containing Monsanto’s Intacta RR2 PRO technology.

Monsanto says to plant seeds grown with that technology without paying royalties - something that the current law allows - amounts to copyright infringement.

The government says it will introduce a bill to Congress next month requiring farmers to pay royalties for the first three seasons of planting beans grown from original GMO seeds.

“That’s something we are not so willing to grant,” said Dardo Chiesa, president of Argentine Rural Confederation (CRA), one of the country’s main farmers associations.

Grains powerhouse Argentina is the world’s No. 3 soybean exporter and top supplier of soymeal livestock feed.

Monsanto officials in Buenos Aires said they would have no comment on the bill until the measure is formally introduced.

“We are worried about it,” said Jorge Solmi, head of the seed committee at the Agrarian Federation of Argentina (FAA), another major growers’ organization.

President Mauricio Macri was elected last year on promises of rejuvenating Argentina’s economy through a series of free-market reforms.

The farm sector has generally been supportive of Macri, but the conflict with Monsanto remains a sore spot.

The government said in June it would oversee the testing of soybean crops under a deal aimed at satisfying Monsanto’s demands that its genetically altered technology be protected.

Monsanto wanted exporters to inspect shipments as they do in neighboring Brazil but Argentine farmers opposed that and asked for government control. Monsanto had threatened to stop selling new soybean technologies in Argentina over the dispute.

This year’s soy harvesting has been completed in most parts of Argentina. The government expects the crop to amount to 58.8 million tonnes.