Livestock carrier Gulf Livestock 1 sent a distress signal at 4.45am (NZT) yesterday in the East China Sea, an area being affected by Typhoon Maysak.
NHK World Japan reported that the Panamian registered cargo ship issued the distress signal at 1.40am Wednesday Japan time from a ship about 185km west of Amami Oshima in southwest Japan.
It reported that the coast guard has sent out patrol ships to search the area.
The ship departed Napier on August 14 carrying 5800 cows and reportedly 43 crew members including two people from New Zealand, 39 from the Philippines, one from Australia and one from Singapore.
It was expected to arrive in China on September 3.
Japanese media and several marine tracking websites have reported the missing ship.
NHK World reported that at shortly before 7pm Wednesday Japan time Japan's Defense Ministry said crew on a patrol plane spotted a lifeboat-like object in the waters near where the signal was sent and a person in a lifejacket nearby.
New Zealand's Agriculture Minister Damien O'Connor has been briefed on the missing ship.
Because it was an overseas incident, the Ministry for Foreign Affairs was the lead agency, a spokesperson said.
Safe Campaigns Manager Marianne Macdonald said it highlighted the risk of exporting cattle. The cows are "likely all pregnant", she said.
