Interislander said in an update it had to cancel two morning sailings of the Aratere today.
The ship was supposed to depart Wellington at 6.15am and return from Picton at 11am.
“All passengers have been shifted to other sailings and we are putting on additional sailings on Sunday morning to assist passengers to get across the Strait,” it said.
“The weather will be monitored over the weekend and further delays or disruptions are possible.”
Bluebridge said on its website “conditions in the Cook Strait have deteriorated with strong winds and large swells present”.
Its 2am and 1.30pm sailings out of Wellington have been cancelled, and the sailing at 8.15am operated as freight-only.
Two crossings from Picton to Wellington have also been cancelled, one at 7.45am and another at 7.15pm.
“Customers impacted by these cancellations will be contacted by our team for alternate sailing options,” the update said.
“We will continue to monitor the forecasts closely and if further cancellations occur, customers will be notified as soon as possible.”
MetService meteorologist Pierre Foucaud said there had been 3-4m swells today with winds gusting to 50 knots.
“We are on an easing trend today but we expect another increase tomorrow afternoon, with a gale again from 40-45 knots tomorrow afternoon into tomorrow evening,” he said.
Foucaud said MetService expects the swell to rise to 4m on Sunday evening.
“From tomorrow afternoon, we expect stormy conditions with winds up to 50 knots, lasting for about 24 hours into Monday evening,” said Foucaud.
He said a swell of 3-4m can be expected until late Monday evening.
Interislander advises any passengers concerned about seasickness to sit towards the rear of the ship, rather than the bow (front) which experiences the most movement.
“Don’t sail on an empty stomach, and consider sipping ginger ale.”
It also recommends taking seasickness pills.