Chilean salmon farmer Nova Austral is facing accusations it failed to report the escape of hundreds of thousands of salmon in November, despite the company's denials.

Chile's National Fisheries and Aquaculture Service (Sernapesca) claims between 268,000 and 387,000 fish escaped from a farm in Chile's southern Magallanes region.

The company initially denied there had been an escape from the site, named Skyring 3CC 120208, before blaming the disappearance of fish on sea lions.

Sernapesca reported the salmon producer to Chile's environmental authority (SMA) for not immediately notifying authorities of a possible escape.