However, Port Otago chief executive Kevin Winders said he was hopeful parent company Carnival Corporation would pick up other bookings to fill the gap it left in coming years.
Mr Winders said it was "pretty tough" for the cruise industry in New Zealand at present, but this was a cost-management exercise.
Carnival Corporation chief executive Josh Weinstein said the company would remain committed to the region.
"P&O Cruises Australia is a storied brand with an amazing team, and we are extremely proud of everything we have accomplished together in Australia and the broader region."