By Alexander Villegas

Feb 18 (Reuters) - An oil and gas workers' union in Argentina's oil-rich Chubut province threatened to strike on Tuesday after Halliburton laid off hundreds of workers and decided to close its local office.

Speaking on the union's broadcast radio channel, Carlos Gomez, deputy secretary of the Chubut Private Oil and Gas Union, said the company walked back commitments to maintain staffing levels and laid off 290 workers on Monday night without prior notice to the union.

Chubut is Argentina's second-largest oil-producing province with an output of about 7.4 million cubic meters in 2024, about 20% of the country's total production.

Companies like state oil firm YPF have been selling mature oil field assets to focus on the country's massive Vaca Muerta region, one of the world's largest shale oil and gas formations.

Halliburton did not immediately respond to a request for comment, but Gomez said the company blamed the layoffs on reduced work in the area and its inability to guarantee profits.

The union filed a complaint with the regional labor authorities and requested a mandatory conciliation to reach an agreement with Halliburton by Friday.

"If the mandatory conciliation ends without Halliburton fixing the problem with the nearly 300 fired workers, both unions will go on a general strike in all oil and gas fields," Gomez said. The union represents about 8,000 workers.

The union would join workers in neighboring Santa Cruz province who have been on strike since last week to halt YPF's departure from the area, which produces about 10% of the country's oil.

(Reporting by Alexander Villegas in Santiago; Editing by Richard Chang)

((Alexander.Villegas@thomsonreuters.com; +56 9 9818 8538))