A time exposure shows a star leaving a trail over the summit of the world's highest mountain Mount Everest, also known as Qomolangma, at sunrise in the Tibet Autonomous Region May 7, 2008. Heavy snowfall during the past week has hampered efforts for the Olympic torch's ascent of Mount Everest, but the team of 31 Chinese climbers, 22 of them ethnic Tibetans, are fixing routes and repairing camps for the final assault on the summit. REUTERS/David Gray (CHINA)

A South Korean mountaineer has gone missing after climbing the world's highest mountain, Seoul's foreign ministry said on Monday.

Song Won-Bin, 44, went missing on Saturday while returning to base camp with several other climbers after scaling Mount Everest in the Himalayas, a ministry spokeswoman told AFP.

She said a search would begin soon, but did not elaborate further.

Yonhap news agency said Song had collapsed due to altitude sickness and fallen off a cliff. It quoted a diplomat in the South Korean embassy in Kathmandu.

It said the climbers were part of a team of graduates from the same high school in the central city of Daejeon.

The team of about a dozen members flew to Nepal at the end of March to mark their school's 50th anniversary by climbing the 8 848-metre peak. They were due to return home later this month.

The disappearance comes after three South Koreans including renowned climber Park Young-Seok went missing during an attempt to scale Annapurna last October.

More than 3 000 people have climbed Everest, which straddles Nepal and China, since it was first conquered by Edmund Hillary and Tenzing Norgay in 1953.

Every year hundreds more set out in April to attempt the climb when conditions are at their best. - Sapa-AFP