Firefighters were struggling to control the blaze that started at around 8.30am local time in Gangneung, with water-bombing aircraft unable to take off due to the winds, officials said.

The flames had consumed more than 170 hectares (420 acres) of land and prompted the evacuation of some 300 residents in the city of more than 200,000 people as of 1pm, Gangwon Province governor Kim Jin-tae said. There were no immediate reports of any casualties.

The fire appears to have started after strong winds blew a tree over onto live overhead power cables, igniting flames, Kim said.

Photos and footage circulating on social media showed fires razing forests and fields, and buildings engulfed by smoke.

South Korean president Yoon Suk Yeol ordered officials to mobilise all available resources to put out the fire as soon as possible and quickly evacuate nearby residents to minimise casualties, his office said.