NEW YORK (Reuters) - A Puerto Rican official on Tuesday said the overhaul of the U.S. tax system, if not amended, could devastate the bankrupt U.S. territory’s ability to collect desperately needed revenues.

Francisco Pares, an assistant secretary in Puerto Rico’s treasury department, said a major tax overhaul approved over the weekend by the U.S. Senate could erode “approximately a third of the total revenues Puerto Rico earns through its tax system.”

Speaking at a New York meeting of Puerto Rico’s federal financial oversight board, Pares said local government leaders are lobbying Washington for changes that would exempt Puerto Rico from a part of the legislation that proposes taxing U.S. companies on foreign earnings.

Puerto Rico, despite its territory status, is considered a foreign jurisdiction for tax purposes, so it would be subject to the tax. Local officials have said that could spur U.S. companies to shutter Puerto Rican operations, threatening tens of thousands of manufacturing jobs there.

Talks will begin, likely this week, between the Senate and the U.S. House of Representatives, which approved its own version of the legislation, to reconcile the two bills.

In a press conference after the meeting, board Chairman Jose Carrion said he had met with the office of U.S. House Speaker Paul Ryan, and “expressed concern about the [tax] legislation and its potential impact on Puerto Rico.”

Natalie Jaresko, the board’s executive director, said she had met with U.S. Rep. Peter Roskam, the Illinois Republican who chairs the House Subcommittee on Tax, and sought assurances that “the enterprise of Puerto Rico not be discriminated against.”

Puerto Rico, with $120 billion of combined bond and pension debt and near-insolvent public health systems, filed the largest-ever U.S. government bankruptcy earlier this year.

Then, in September, as it was negotiating a debt restructuring with creditors, the island was slammed by Hurricane Maria, which killed dozens, decimated infrastructure and spurred emigration. The storm sent Puerto Rican bond prices plummeting, trading as low as around 20 cents on the dollar.

Gerardo Portela, head of Puerto Rico’s financial authority, said at Tuesday’s meeting the island’s revenue collections were 37 percent lower than forecast in October.

Jaresko stressed the need for Puerto Rico to focus on structural reforms when putting together a fiscal turnaround blueprint, a revised draft of which is due on Dec. 22. The plan will serve as a baseline for debt restructuring talks.

Some island bondholders want to delay a restructuring and have complained that the board, and the Puerto Rican government it represents, are trying to capitalize on depressed bond prices to strengthen their negotiating positions ahead of talks.