The flooding caused the cancellation of a dog agility competition in Hamilton.

The storm coming in at Te Uku near Raglan.

The clean-up in storm-hit regions of the country has started, with wild weather leaving behind nearly 100 homes flooded, pensioner flats evacuated and roads seriously damaged.

Storms brought flooding, slips and even a tornado, with the parts of Richmond and Stoke in the Nelson-Tasman region worst hit, with near-record 122.8 millimetres of rain. Parts of Hamilton and the Bay of Plenty also experienced flooding.

The Nelson-Tasman Region Civil Defence and Emergency Management Group Emergency estimated at least 90 homes in the Tasman District had been flooded and were being checked by building inspectors.

ALDEN WILLIAMS/Fairfax NZ An abandoned car on Main Rd, Stoke.

All commercial properties which were flooded were checked by environmental officers, with no major issues reported. Six pensioner cottages were flooded and five were evacuated.

In Nelson, there was serious damage to the roads and paths within the Saxton Field complex, forcing its closure for at least a week.

"The most affected area within the Nelson region is along Orphanage Creek in Stoke," Angela Ricker from civil defence said.

Metservice MOVING INLAND: Metservice rain map shows a massive thunder storm moving toward Hamilton.

"Residences and businesses in this area seem to have suffered the worst, with many shops suffering stock damage and roads covered in mud."

A new band of heavy rain is expected in the early hours of the morning.

MetService has kept in place a severe weather warning, saying more torrential rain would be expected for the northern regions of both islands.

"Further bursts of heavy rain are likely about parts of Bay of Plenty, Taranaki and northern Marlborough through to Monday afternoon, MetService said.

"Another 50-100mm of rain is likely in some of these areas on top of what has already fallen, with possible thundery downpours of 25mm per hour."

The welfare centre would be moved to the Tasman District Council tomorrow and welfare representatives would be there during business hours.

Throughout the affected areas, stormwater drains and intakes are being cleared out, but debris on the roads is still entering the system.