(Adds that Mitsui declined to comment, last paragraph)
By Jeb Blount and Marta Nogueira
RIO DE JANEIRO, Dec 3 (Reuters) - A Brazilian court blocked the planned 1.9-billion-real ($509 million) sale of 49 percent of Gaspetro, the gas pipeline unit of Petrobras, to Japan's Mitsui Co, a move that could frustrate the state-run oil company's efforts to sell assets to cut debt.
Judge Manoel Ricardo Calheiros D'avila of the Justice Tribunal of Bahia issued the injunction on Wednesday on behalf of the government of the state of Bahia. Bahia owns 51 percent of Bahiagás, controlling under a shareholders agreement with Gaspetro and Mitsui, which each own 24.5 percent.
In his ruling, made public by the court on Thursday, the judge said the state's concern that the sale of the Gaspetro stake to Mitsui could undermine its control of the company under the shareholders' agreement was valid and suspended the sale until the merits of Bahia's concerns can be judged.
Petroleo Brasileiro SA, as Petrobras is formally known, has plans to sell $15.1 billion of oil field, refinery, distribution or other assets by the end of 2016 to maintain a $19 billion expansion plan and keep a lid on its nearly $130 billion of debt, the largest in the world oil industry.
The Mitsui-Gaspetro deal has been the only announced sale so far and is worth only 3.4 percent of Petrobras' asset-sale goal.
Mitsui declined to comment. Petrobras did not immediately respond to requests for comment. Bahiagás confirmed that the injunction had been issued. (Reporting by Jeb Blount and Marta Nogueira; Editing by Marguerita Choy, Chizu Nomiyama and David Gregorio)