The labor minister, Kim Dae Hwan, said, "The government has determined that if the strike by Asiana pilots continues, it would not only cause inconveniences for the people but also threaten the safety of air travelers and hurt the national economy."

The action came after Asiana's management and union failed to reach a compromise in last-minute talks in a mountain resort south of Seoul, where hundreds of Asiana pilots have been staying in a hotel since the walkout began on July 17. The government had given the two sides until Wednesday to reach a deal or face arbitration.

After the emergency arbitration was announced, the Asiana union said it would end the strike. But 1,800 riot police officers were on standby outside the hotel on Wednesday, waiting for an order to move in, in case any of the pilots refused to return to work despite the government order.

Asiana's strike has been the worst for South Korea's aviation industry. Since the walkout began, the airline has been forced to cancel more than 2,200 domestic and international flights, or one-third of its total scheduled flights.The strike has cost the airline an estimated 165 billion won, or $163 million, in lost revenue from passenger and cargo services, the government said on Wednesday.

Asiana has been operating with nonunion pilots and union members who did not join the strike. About 500 of the airline's 839 pilots are unionized. The union said about 400 pilots had been on strike.

Pilots are calling for more rest days and fewer flying hours. They also insist on a say in management decisions and on raising the retirement age to 58 from 55.