A New Zealander is reported to be an unplanned crew member on board the yacht being sailed to Antarctica by Norwegian adventurer Jarle Andhoey.
Norwegian public broadcasting company NRK reported Andhoey saying the boat left New Zealand in a hurry after being told to go by immigration authorities.
Along with himself and three other members of the expedition, he had discovered a New Zealander who had been doing some work in the boat was still on board.
It was a somewhat tricky situation because the man did not have a passport or papers with them, Andhoey told NRK.
The presence of the New Zealander on the trip was not part of the plan. It was just a hectic departure.
New Zealand government agencies have been tracking Andhoey, a self-proclaimed Viking, who left Auckland last weekend on 16-metre steel yacht Nilaya.
The boat was spotted in international waters off the coast of Hawke's Bay on Thursday afternoon.
Andhoey said he wanted to reach McMurdo Sound where last February his polar bid ended with the sinking of the yacht Berserk and the deaths of three men who were aboard it.
Andhoey has told Oslo's Vestfold Blad that he wanted to find the remains of the Berserk and the three men. He also wanted to travel to the South Pole by quad bike.
He does not have approval by any Antarctic Treaty nation for his latest trip.
He also entered New Zealand without declaring he had previously been deported from Canada.
Andhoey told NRK the crew had chosen to sail without an emergency beacon on board, as they did not want to put others' lives at risk in the event of an accident.
They would not take any unnecessary risks.
A Ministry of Foreign Affairs and Trade spokesman said they had not been approached for assistance for the alleged Kiwi stowaway.