Some Interislander ferry services are cancelled from this afternoon with 6m waves forecast in Cook Strait.
The southerly winds bringing large swells to Cook Strait are expected to reach gale force in Wellington this evening.
In the central North Island, heavy snow is forecast which could disrupt travel in the Taihape area.
Interislander cancelled four sailings today and two early morning crossings tomorrow.
- Aratere 1600 from Wellington, 2045 from Picton
- Kaitaki 2030 from Wellington and 0230 (Thursday) from Picton
- Kaiarahi 1830 from Picton and 0200 (Thursday) from Wellington
Interislander executive general manager Walter Rushbrook said all affected passengers would be contacted and transferred to alternative sailings. He said the company regretted the inconvenience to passengers but safety had to be its top priority.
Bluebridge has not announced any cancellations.
Wellington City Council is warning residents of the South Coast to be prepared for the large swells along the south coast from late afternoon.
After huge waves hit the coast in April causing damage to homes a wave warning system was brought in to alert councils and civil defence.
Taupō and Blenheim were sub-zero this morning, both still at -1C by 7am, and colder than Queenstown at 4C, while Auckland and Wellington were 7C.
Temperatures are expected to be low through to Friday.