THREE sailors are missing and others are awaiting rescue after a fire broke out on a Korean fishing boat in the Southern Ocean.

The 51-metre long Jung Woo 2 was carrying 40 crew through the Ross Sea, 3700km southeast of New Zealand, when it issued a mayday call about 3am today.

Rescue Coordination Centre New Zealand spokesman Dave Wilson said three sailors were missing, 25 were floating in a lifeboat and a further 12 remained on the vessel, which is burning out of control.

Three men on board are understood to be injured. One extra lifeboat is available.

Mr Wilson said five vessels were responding to the distress call, including the sister ship Jung Woo 3, which is due to arrive at the scene shortly.

A US research vessel with hospital facilities was about 12 hours away from the Jung Woo 2's reported position, with two other vessels around 10 hours away.

Contact was also being made with Antarctic bases to see if injured could be taken there.

He said weather conditions were good for the rescue, although a low pressure weather system was expected tomorrow.

The 26-year-old Jung Woo 2 was built in Japan and originally named the Koryo Maru 32.

It was sold to Korean-owned Sunwoo Corporation, which uses it to fish for Patagonian Toothfish, rays and crabs in the Antarctic Ocean.

The distress call is the second to be sent from Antarctic waters in recent weeks.

The Russian fishing vessel Sparta, which carries 32 crew, hit ice in a similar position in the Ross Sea in mid December, rupturing the hull.

It was repaired at sea over two weeks before proceeding to Nelson, where it arrived yesterday.

In December 2010, a Korean fishing boat, No.1 Insung, sank in the same area, killing 22.