Washington, Aug 31 (IANS): Typhoon Maysak is slowly approaching the Korean Peninsula on Monday, passing through waters 470 km south of Japan's Okinawa island, the weather office said.

The Korea Meteorological Administration (KMA) said Maysak, this year's ninth typhoon, packing wind gusts of 43 meters per second was travelling northward at a speed of 31 km per hour, reports Yonhap News Agency.

Later in the day, the typhoon is expected to gain force with wind gusts of 49 meters per second.

"When the typhoon makes landfall in the country, it is expected to sustain winds of around 40 meters per second," the KMA said.

"It is highly likely that rains and storm surge on the coastal area could cause casualities and damage to structures, so people should thoroughly prepare for the typhoon in advance."

But its path is still subject to change, Yonhap News Agency quoted KMA as saying.

The typhoon is expected to arrive 320 km south of the resort island of Jeju at on Wednesday morning.

On early Thursday it is projected to make landfall on the southern coast of Namhae and pass inland 20 km northwest of Busan.

It is expected to move over the southeastern cities of Ulsan and Gyeongju and eventually move to the East Sea.