SAO PAULO, Nov 28 (Reuters) - Brazilian beefpacker Minerva will account for 50% of South American beef exports in five years, up from 40% presently, Chief Executive Fernando Queiroz said at an event hosted by the company on Tuesday.

Minerva, which bought plants from competitor Marfrig to boost its presence in South American countries this year, believes processing grass-fed cattle, a system that predominates in the region, is a competitive advantage for firms that operate here.

South America also boasts lower labor costs compared to countries like the United States, Queiroz said of the world's biggest beef producing nation, where Marfrig itself and rival JBS SA own production facilities.

Minerva has made 20 acquisitions over the last 15 years, seeking to be a relevant player in countries like Brazil, the world's biggest beef exporter, as well as in Argentina, Uruguay and Paraguay.

"We have the best global platform to mitigate risks," Queiroz said, referring to the current low cattle availability in the U.S. that is affecting rival companies there.

In August, Minerva announced an agreement worth 7.5 billion real ($1.54 billion) to buy certain cattle and sheep slaughtering units from Marfrig in Brazil, Argentina, Chile and Uruguay.

The move is expected to boost Minerva's slaughter capacity by around 44%, to more than 42,000 heads per day, according to company disclosures.

($1 = 4.8761 reais) (Reporting by Roberto Samora, Writing by Ana Mano, editing by Ed Osmond)