Interislander has provided passengers with tips to avoid seasickness for the other sailings.
A lingering low-pressure system is bringing rain or showers to many parts of New Zealand, with thunderstorms, large swells and strong winds affecting the centre of the country.
Interislander posted a service alert on its website, notifying passengers the 6.15am Picton-to-Wellington crossing on Friday had been cancelled because of the rough sea, as had the 11am return service.
MetService said people could expect 150-200mm of rain there, on top of what had already fallen, especially about the Wairoa ranges. Peak rates would be 10-20mm/h.
Strong wind watches remain in force for the following areas:
Kāpiti Coast, Wellington and coastal Marlborough including the Sounds; to 4pm on Friday.
Taranaki and western parts of Whanganui; to 4pm on Friday.
Coastal areas of Hawke’s Bay and Gisborne/Tairawhiti; to 6am on Saturday.
MetService warned southerly and southwest winds may approach severe gales in exposed places.
In a post on social media, it said large, powerful 4m southerly swells were impacting the south and east coasts of the North Island.
A heavy swell warning was in place for Wairarapa (Turakirae Head to Mataikona) until 8am on Saturday.
Big swells rising to 3-4m would be accompanied by large wind waves developing on Friday morning, MetService said.
These would gradually ease overnight into Saturday morning.
The highest risk period would be about high tide on Friday afternoon, the forecaster said.
