At least five crew on board a South Korean fishing vessel were dead and 17 missing after it sunk in the Southern Ocean early Monday.

Maritime New Zealand said 20 survivors had been recovered from the South Korean fishing boat, while a further five crew were found dead and 17 were still reported missing.

The Rescue Coordination Center New Zealand was advised about 1 p.m. Monday of the sinking of the South Korean owned and operated No.1 In Sung, which reportedly sunk at 6.30 a.m. New Zealand local time (17:30 GMT Sunday), the New Zealand stuff. co.nz news website reported.

The 20 survivors and 5 deceased were now on board the fishing vessel No. 707 Hongjin.

It is not known what caused the vessel, which is 58 meters long, to sink or why no distress communication was received prior to it sinking.