Argentina's Supreme Court ordered the state-controlled energy firm YPF to fully disclose its contract with Chevron Corp amid allegations of secret clauses in the agreement.
Chevron in 2013 signed a deal to explore the barely tapped Vaca Muerta shale formation, an accord that marked the largest foreign investment in Argentina's energy sector since the government seized Spanish giant Repsol's controlling stake in YPF.
Opposition lawmakers believe the contract contains secret clauses that hand concessions to Chevron and undermine national interests.
The Supreme Court said YPF "cannot deny access to information of unquestionable public interest."
The Argentine government holds a 51 percent stake in YPF.
The energy company said on Tuesday in a statement it would comply with the ruling.
YPF has previously said that all its actions are in accordance with Argentine law and that it meets all obligations required of a company listed in Buenos Aires and New York.
Covering an area the size of Belgium, Vaca Muerta is one of the world's largest shale formations.
Chevron and YPF have announced joint investments that could total as much as $15 billion under the terms of the accord.
YPF estimates $200 billion in investment is needed over the next decade to exploit Vaca Muerta and reverse a gaping energy trade deficit.
The company said on Friday that a total of 388 shale oil and gas wells have now been drilled, primarily in the Loma Campana concession where it is operating alongside Chevron.
Shale production surpassed 50,000 barrels of oil equivalent per day in October, YPF added.
