Many roads in the Clutha district in the South Island are closed by fallen trees toppled by strong winds.
The local council said some of the trees might not be safe for contractors to move until daylight.
It was asking people to avoid all unnecessary travel and stay off the roads.
People are also being told to keep a torch handy in case there are power outages.
Meanwhile, MetService has issued a severe wind warning for westerly gales in exposed areas of Southland and inland Canterbury.
It said the strong winds would be over the lower South Island and could gust up to 120km in coastal Southland and in the Canterbury high country and possibly Banks Peninsula.
A front is moving north-east across the South Island today.
A strong wind watch is in place for inland Marlborough, Tararua district, Wairarapa and Hawke's Bay, south of Hastings.
Severe Weather Watches and Warnings have been issued for severe westerly quarter gales today. While this will ease this evening, winds could pick up again on Thursday and more Watches/Warnings could be issued. For full details: https://t.co/qHyE5zhh6X ^CRB pic.twitter.com/5YL6GFy1Sw— MetService (@MetService) May 14, 2019
Severe weather forecaster William Nepe said the windy weather pattern was typical for this time of year.
"Autumn and spring, we see systems like this all of the time."
He said another period of severe gales is possible tomorrow but winds were likely to ease off by late evening.
Mr Nepe said the high winds today and tomorrow had the potential to cause damage, with trees and powerlines likely to be knocked down.
The New Zealand Transport Agency is advising that people using high-sided vehicles, campervans, caravans and motorbikes to take care because of strong winds.
Roads affected are State Highway 7 near Hanmer and over the Lewis Pass, and State Highway 8 from Twizel to Fairlie, State Highway 80, Ben Ohau to Mt Cook and State Highway 82 from Ikawai to Kurow.