South Korea fishing boat sinks in Southern Ocean
The ship is said to have gone down more than 2,000km (1,250 miles) south of New Zealand.
Eight of the crew were South Korean; eight Chinese, 11 Indonesians, three Filipinos and one Russian were also on board, Seoul's Yonhap news agency said.
South Korea's foreign ministry said the 614-tonne ship sunk at around 0430 South Korean time on Monday (1930 GMT on Sunday).
Twenty sailors were rescued by another fishing boat operating nearby, the South Korean foreign ministry said in a statement.
Seoul said it had asked New Zealand to help in the rescue effort.
New Zealand's maritime spokesman Ross Henderson told AFP that all vessels in the remote area had been told to go to the site to help search for survivors. A helicopter has also been sent to the area, he said.
There had been no distress call before the ship sunk, he added.