High winds and heavy swells in lower North, upper South islands

High winds and heavy swells in the lower North and upper South islands could cause some disruption.

MetService has issued a strong wind warning for Wellington, Marlborough east of Seddon and the Marlborough Sounds from 8pm Thursday, warning damage to trees, powerlines, and unsecured structures is possible.

Swell warnings are already in effect for the southern coasts of Wellington and Wairarapa.

Cook Strait ferries Interislander and Bluebridge cancelled some sailings across Thursday and Friday with Bluebridge cancelling an additional sailing on Saturday.

MetService said waves rising to six metres could be expected early on Friday morning, with waves peaking near seven metres late on Friday morning.

However, Wellington Civil Defence Emergency Management said the swell heights in the warnings are not currently forecast to be at the same level as a few weeks ago and it is unlikely there would be any evacuations.

The Transport Agency is also urging drivers to take extra care when travelling, saying road users need to be ready for strong winds, particularly drivers of high-sided vehicles (vans, trucks, campervans), towing vehicles, light vehicles, and motorcyclists.

"Caution will be needed on exposed routes like Wainui Saddle on State Highway 1 Transmission Gully and State Highway 2 Remutaka Hill. Cyclists and pedestrians should also exercise care on the Ngauranga to Petone shared path," the agency said.

"This will affect traffic on State Highway 1. People travelling between Picton and Ward should exercise caution on the route."

Road users are advised to drive to the conditions.