SANTIAGO, Dec 14 (Reuters) - Workers tied to Chile’s civil aviation authority announced a 48-hour strike for Thursday and Friday this week, potentially causing airport chaos just as the country gears up for the Christmas holidays.

In September, a 24-hour strike stranded thousands of passengers and led to long lines at airports, after a majority of workers affiliated with the DGAC, or civil aviation authority, went on strike to demand improved benefits and working conditions.

After two months of negotiations, DGAC workers, which includes air traffic controllers, said on Monday that they had rejected the government’s proposal for a state subsidy to improve their pensions.

“The workers agreed to go on strike for 48 hours on Thursday and Friday,” union head Jose Perez told Reuters.

“Unless there is an improvement in the government offer very soon, the stoppage will go ahead,” he said.

The DGAC said dialogue with workers was ongoing, but that services would be disrupted if the strike goes ahead.

Chile’s flagship airline LAN, part of LATAM Airlines , which suffered dozens of canceled flights during the September work stoppage, said it was awaiting more information from the government to decide on measures it could take to mitigate the impact of the strike. (Reporting by Antonio de la Jara, writing by Rosalba O’Brien, editing by G Crosse)