SAO PAULO, March 4 (Reuters) - A recent wave of farmer bankruptcy filings in Brazil is a concern for the South American farming powerhouse, the chief executive officer of U.S. grain trader Cargill's Brazilian unit said on Monday.

Paulo Sousa was speaking at an event in Sao Paulo hosted by a financial services firm to discuss the challenges and opportunities for agribusiness firms in Brazil, the largest exporter of soybeans, sugar and other food commodities.

"There is a wave of bankruptcy filings, a legal novelty that brings a lot of concern to the sector," Sousa said.

Brazilian traders have become increasingly vocal about the problem.

The rise in farmer bankruptcy cases, which affects delivery of committed grains, may also hamper traders' ability to complete export programs, grain exporters lobby Anec said last month. (Reporting by Ana Mano Editing by Chris Reese and Sam Holmes)