"Following several reconnaissance flights, the fire's perimeter was updated with greater accuracy, estimating an affected area of 3,527 hectares," the park's administration said in a press statement, Xinhua reported.
The area, it said, was shrouded in smoke Friday morning, which spread across nearby valleys and prevented aerial operations to combat the blaze.
Access from Los Rapidos to the Circuito Cascada los Alerces area would remain conditionally restricted over the weekend, allowing only authorized vehicles from official institutions and local residents, it added.
Established in 1934, Nahuel Huapi National Park spans 710,000 hectares across the southern provinces of Neuquen and Rio Negro. It is Argentina's first national park and protects Andean ecosystems in northern Patagonia, water basins, wildlife and a diverse cultural heritage.