The rain-soaked West Coast is bracing for the possibility of more thunderstorms today, while strong, possibly damaging winds are forecast to lash Christchurch, Marlborough and Wellington.
Meanwhile, the rest of the country remains unseasonably warm.
Severe weather on the West Coast forced road closures last night and prompted warnings of possible thunderstorms and tornadoes.
West Coast rivers were being closely watched overnight, and one road has been closed.
State Highway 67 was closed last night between Hector and Little Wanganui, south of Karamea, after a creek burst its banks. Caution is also urged on SH67 from Westport to Hector due to surface flooding.
NZTA said this morning there were four known wash-outs on the road.
SH67 remains closed with 4 known washouts in the area. All other Coast Rd's remain open at this point in time. ^SM pic.twitter.com/3zo2D4dXFV— NZTA Canterbury/WC (@NZTACWC) May 11, 2016
There was no indication yet as to when the road may reopen.
A MetService warning for the region indicates heavy rain through until at least Sunday, and a Weatherwatch analyst said rain was expected to get heavier in the afternoon with possible thunderstorms, before easing overnight.
Nearly 200 people had to be evacuated when the Waiho River burst its banks in Franz Josef after downpours in March.
MetService also warned of strong and possibly damaging winds around Christchurch, Marlborough and Wellington today.
Meanwhile, temperatures remain unseasonably warm for much of the country, with highs of more than 20c degrees expected in Canterbury, Tasman and the upper North Island.
Christchurch recorded a high of 26.2c yesterday - the third highest May temperature on record. MetService said it had only been warmer in May 1978 and May 2015.