RIO DE JANEIRO - Brazilian Olympic beach volleyball coach Marcio Sicoli has been accused of child abduction by the family of his estranged wife.

US authorities have agreed to cooperate with Brazil's federal department of human rights, which has requested a search and arrest warrant for the 32-year-old, Lancenet reported.

The conflict began in January when Isabel Bierrenbach agreed to allow her three-year-old son to visit his father in California.

But Sicoli, who coaches the USA's two-time Olympic gold medalists Kerri Walsh and Misty May, has refused to let the child return to Brazil, entering in a custody battle with Californian authorities.

Bierrenbach responded by notifying Brazilian authorities and requesting the child's immediate return to Brazil.

According to Lancenet, the US government ordered the case be brought before a Californian court, adhering to the Hague Convention's child protection laws, to which Brazil and the US are signatories.

A hearing has been scheduled for June 4 after two previous sittings were postponed due to alleged health problems suffered by Sicoli's lawyer.

"The family needs to think in the best interests of the child because the legal processes are long and it's the child who will suffer the most," said Brazil's federal human rights minister Maria do Rosario in comments reproduced by UOL.

"It's not reasonable to have this dispute. Our first objective is to mediate the conflict and contribute so that the child returns to Brazil where he is a legal resident.

"The custody dispute should occur in the country where the child resides, according to the Hague Convention."

The child's maternal grandfather, Reinaldo Bierrenbach, reportedly told O Globo that Sicoli was adamant about gaining custody, having refused a proposal allowing him to stay with the child on a periodic basis.

Sicoli and Bierrenbach were married in 2005 and relocated to Los Angeles in 2007 before separating last year. The mother returned to Brazil with the child last October.

Born in Los Angeles, the child has an American and Brazilian passport.Sicoli and his lawyers could not be reached for comment by Xinhua on Sunday.