The Italian adventurer, Alex Bellini, who is rowing across the Pacific, is near the edge of New Zealand's ocean rescue zone and should reach Sydney by mid-November.
He has been at sea since leaving Peru in February and if successful will be the fifth person to row across the Pacific from east to west.
This month he passed through Tongan waters and said on his website that the currents went crazy as the sea floor rose and one area may have been affected by underwater volcanic activity.
In July, Mr Bellini was spotted near Tuamoto atoll in French Polynesia, after being alone for 136 days.
At the time, he told authorities his main concern was that his jar of Parmesan cheese was emptying too quickly.
There's no word as to whether it has run out.