Incoming heavy rain could be the biggest weather event locally since devastating floods nearly a year ago, Tasman District Council says, with a wash of weather and flood warnings on both the North and South Islands.
Heavy rain warnings have been issued for potential flooding and slips for various South Island regions, followed by weather warnings and watches for Taranaki, Northland, Auckland and Bay of Plenty. The storm is expected to last until Tuesday for some places.
MetService forecasters say the heavy rain could begin Sunday for northern and western parts of the South Island, from midnight into Monday at Taranaki, and from noon and 6pm on Monday for the Northland and Bay of Plenty, respectively.
Authorities in a number of regions have asked people to prepare for the storm, and for drivers to take extreme care on the roads as the long weekend winds up. In Marlborough the emergency management team has been activated.
People in Tasman warned to prepare for significant event
Tasman District Council said locally “this event will be the largest” weather event for some areas since widespread flooding wreaked havoc and caused an estimated $50 million in damage in June and July 2025. And at the very least, this current storm will be “at least a moderate event,” they said.
People in the region have been asked to stay off the roads.
The heavy rain warnings for Tasman are expected to last until 4am Tuesday, and significantly impact: Golden Bay, the Tākaka Hill, Riuwaka River, Upper and Lower Motueka and the Richmond Ranges behind Nelson and Richmond.
“With a long-duration rainfall event and potential heavy falls towards the end of the period, both slips and treefall risk are high towards the end of the warning period. Surface flooding is likely in all areas, including elevated flows in small streams,” Tasman District Council said.
“High tide on Monday night is likely to coincide with the strongest of the NNE winds. Wind gusts could reach 60km/h in exposed places,” while coastal erosion was also expected during the storm and streams and rivers could rise quickly in thunderstorms.
🟧🟨❗️Severe Weather Warnings and Watches have been updated for Significant Heavy Rain over large parts of Aotearoa and northerly gales over the Canterbury High Country. 🌧️🍃
All the details herehttps://t.co/os2FgIcKqk@NZcivildefence @nztamain pic.twitter.com/ZnMmVzDpYO
— MetService NZ (@MetService) May 30, 2026
What regions have warnings and watches been issued for?
Orange heavy rain warnings: Westland, Fiordland, headwaters of the Canterbury lakes and rivers, Tasman District, Nelson City (including the Richmond and Bryant Ranges and the Rai Valley), the Buller Ranges, Taranaki Maunga, Northland.
Yellow heavy rain or strong wind watches: The headwaters of Otago lakes and rivers, Auckland and Great Barrier Island, the Taranaki Region, Auckland and Bay of Plenty and Rotorua, Taupō, Tongariro National Park, the Marlborough Ranges, Bay of Plenty, Rotorua, Coromandel Peninsula.
A strong wind watch for the Canterbury high country has now been cancelled.
Heavy rains could stall over Marlborough, council warns
The effects of the storm could be magnified by prolonged rain on Tuesday morning if the weather system stalls over the southern Richmond Ranges, Marlborough District Council warned.
The region’s emergency management team was activated to ensure the district is as prepared as possible.
The council says based on the MetService forecast at Sunday evening, high water levels are expected in the Pelorus River that are likely to cause flooding at Dalton’s Bridge on State Highway Six.
Motorists are being asked not to travel overnight for the next few days, especially on State Highway Six in the Havelock/ Pelorus/ Canvastown area, because the road could flood or be closed.
Widespread warnings: possible flooding and highway closures, cautions to drivers
Flooding, slips and dangerous driving conditions are possible in affected areas, MetService warned.
By mid-afternoon Sunday, there was already surface flooding on State Highway 6 – the main route linking West Coast towns, as well as strong winds, and the weather was making driving hazardous, the Transport Agency said.
NZTA warned people travelling in the west and top of the South Island to be ready for potential highway closures as well as hazardous driving conditions. It said motorists travelling between Hokitika and Haast should be especially careful, with up to 450mm of rain forecast for Westland until 8pm Monday.
West Coast Emergency Management said the rain arrived there slightly later than forecast on Sunday, and it would continue monitoring developments.
Since 4am Sunday, 81.8 millimetres of rain was recorded in Milford Sound, and about the same south of Hokitika.
In the North Island, Taranaki Maunga could get up to 300 millimetres of rain before 9am Monday, and Northland could get up to 200 millimetres of rain in localised places, before 8am Tuesday, MetService forecasters said.
Roads at risk include:
SH60 – Richmond to Collingwood
SH6 – Hira to Havelock
SH6 – Nelson to Murchison
SH65 – O’Sullivans Bridge to Lewis Springs
SH63 – Wairau Valley
SH1 – Blenheim to Seddon
Drivers have been urged to stay up to date on road and weather conditions as roads may close at short notice and affect King’s Birthday long weekend travel plans.
“Ignoring a closure not only puts your safety and those of your passengers at risk but also endangers emergency service staff who may have to rescue you,” an NZTA spokesperson said.
Westland Mayor Helen Lash was hopeful the weekend’s heavy rain would be manageable for the region as it was expected to arrive over a long time.
