After a week of summery weather, it was inevitable something foul would eventually come along.
A MetService spokesman said an intense area of low pressure was expected to move from the Tasman Sea to the south of the South Island tomorrow, while an associated front moves northeast over southern New Zealand.
"Several warnings and watches have already been issued for the severe weather that this weather system is expected to bring," he said.
"There is high confidence that rainfall amounts will reach warning criteria in the west of the South Island, from Fiordland to northwest Tasman, with significant spillover into the headwaters of the Otago and Canterbury lakes and rivers.
"There is also high confidence that severe northwest gales will affect the Canterbury high country, Wellington, and Wairarapa, while there is moderate confidence of severe northwest gales about Stewart Island, Fiordland, Southland, Otago, the Canterbury coast and plains, and Marlborough."
He said there was likely to be damage to trees, powerlines and unsecured structures in these areas.
"Driving may be difficult, especially for high-sided vehicles and motorcycles.
"Prepare your property by securing items that can be picked up by strong winds and drive cautiously."
On Monday, a front preceded by strong northwesterlies and followed by strong westerlies was expected to move northwards over central New Zealand and on to the north of the country while weakening.
Those westerly winds were likely to reach severe gale force about Stewart Island, and coastal parts of Southland and Clutha for a time, he said.He urged residents to keep up to date with the latest forecasts.
On Tuesday, a west-to-northwest flow would cover the country, and the weather would be calmer, he said.
