The Kaiarahi. Photo: Supplied / InterIslander
Two Interislander ferry sailings were cancelled on Tuesday afternoon, with swells expected to reach five metres in the Cook Strait.
A Bluebridge spokesperson confirmed they would also be cancelling services until the weather cleared.
Southerly gales are buffeting the capital, with the large swells likely to persist through Wednesday.
Interislander alerted passengers on social media of the cancellations of the 8:30pm and 2:30am sailings of the Kaiarahi.
An update for its two Wednesday sailings will be provided at 5.30am.
Interislander said conditions would likely be rough and unpleasant, and it was offering full refunds to anyone choosing not to travel then.
But with the service fully booked, it warned it might be difficult to find an alternative sailing in the next few days.