The nation’s two largest flight carriers ― Korean Air and Asiana Airlines ― are expected to raise fares for domestic flights ahead of the peak summer season, possibly affecting other low-budget carriers in the coming weeks.

Asiana Airlines said Friday that it will increase fares of all domestic flights by an average of 9.9 percent from Aug. 3, the first hike since August, 2004.

The company said the price hikes would amount to 6 percent for Monday to Thursday flights, 12 percent for Friday to Sunday flights and 15 percent for holidays.

Late last month, Korean Air, the biggest domestic carrier, had also hinted at raising fares for all domestic flight by 9.9 percent on average from July 18.

Under the new pricing policy, a flight between Gimpo and Jeju will increase from 73,400 won to 82,000 won ($64-71) for weekdays and 92,900 won to 107,000 won for holidays and weekends.

“Coupled with the consumer price hikes and increases in costs, the development of alternative means of transportation has led to a decrease in passenger demand,” said an Asiana official.

Other smaller low-cost airlines such as Jeju Air and Jin Air have yet to announce any change in fares. But industry sources predict price hikes will be unavoidable as they have maintained fares at about 80 percent of those charged by the two leading airlines.

By Lee Ji-yoon (jylee@heraldcorp.com)