The visit of the giant Ovation of the Seas cruise ship will require reasonably calm weather conditions for the vessel to dock in Port Chalmers next week.
Its height above water level and limited draft means the ship can act as a sail, so any winds above an average of 15 knots with gusts of 30 knots means it will not be able to berth once it approaches the wharf.
Port Otago marine and infrastructure general manager Sean Bolt said stronger winds would blow the ship around too much for it to berth.
Mr Bolt said all ships were prone to what was called "windage", but cruise ships were prone more than others because so much more of the vessel was out of the water, in relation to what was under the water.
The bigger the ship, the more it was affected.
Mr Bolt said it depended on the time of year and the time of day, but "we do have winds over that level quite often, so fingers crossed".
