MetService says cold weather is continuing to spread over the country and thunderstorms and severe gales are expected to be on the way.
The weather forecaster is describing the cold blast as a "significant event".
MetService meteorologist Daniel Corbett told Morning Report the cold front currently sitting across Canterbury is expected to move up to the lower North Island on Wednesday.
Behind that is a second front, with colder air and the possibility of thunderstorms, more showers and the risk of snow levels much lower than seen in the last few weeks, he said.
Mr Corbett said Invercargill had not yet seen snow but the city, along with Dunedin and Christchurch, can expect more cold weather and rain on Wednesday.
"Folks that live out of town or anything about 200-300 metres, that's where we have to watch the risk of snow," he said.
Mr Corbett said a low would bring winds of up to 120 kph to the Wellington region from lunchtime on Wednesday.
Federated Farmers Southland meat and fibre chair Andrew Morrison says farms in the region are well prepared to weather the severe front.
He says stock is in good condition and there is plenty of grass cover.