SAO PAULO, April 13 (Reuters) - Brazilian steelmaker CSN has asked the nation's antitrust watchdog for permission to appoint members to the board of rival Usinas Siderúrgicas de Minas Gerais SA, in which it owns a significant stake, because it is dissatisfied with some directors, Valor Econômico newspaper said on Wednesday.
Cia Siderúrgica Nacional SA, as the company is formally known, says the two board members representing minority shareholders in Usiminas have failed to meet their fiduciary duty, Valor reported, citing CSN Vice President Paulo Caffarelli.
Cade, as the Brasilia-based regulator is known, had ruled in March 2015 that CSN could not have direct participation in the board of Usiminas, which is jointly controlled by Nippon Steel & Sumitomo Metal Corp and Techint Group.
According to Caffarelli, CSN sought Cade's permission to appoint a combined three members to Usiminas' board of directors and financial committee, Valor said.
None of the companies had an immediate comment on the Valor report.
CSN is Brazil's most indebted steelmaker and ranks third in the nation's flat steel market, behind Usiminas.
Usiminas is struggling with a rift between Nippon Steel and Techint as well as fallout from Brazil's worst recession in over a century. CSN had 14.1 percent of Usiminas' voting shares and 20.7 percent of the non-voting stock at the start of last year.
CSN spent about 3 billion reais ($860 million) throughout 2011, when it started to buy shares of Usiminas ahead of the entry of Techint into the company's controlling bloc. The stake is currently worth less than 500 million reais, according to Valor.
$1 = 3.4875 Brazilian reais Reporting by Guillermo Parra-Bernal; Editing by Lisa Von Ahn