The Interisland Line says some Cook Strait ferry services are being disrupted by staff illness and poor weather.
It says the crossing from Wellington at 8.25am and a return sailing from Picton at 1.45pm will be cancelled from Thursday to Sunday inclusive.
Interislander general manager Thomas Davis says due to staff illness, there are not enough ship captains familiar with the ferry Kaitaki.
Mr Davis says the Arahura will be given extra crew members to enable more passengers to be carried.
Most of the affected passengers have been transferred to other crossings and a backlog of freight is the main problem, he says.
The company has apologised for the disruption but adds that strong, southerly swells are also affecting sailing times, causing delays.
