MetService had warned that heavy snow would fall today about eastern Southland and Clutha, and 15cm to 25cm could accumulate above 300 metres until midnight tonight, especially about the Catlins.
The combination of strong southwesterlies and snow showers is likely to bring blizzard conditions, putting vulnerable livestock at risk, MetService warned.
The snow will also affect many roads and may cause disruption to transport.
Ms Flynn said the snow level would rise tonight, but there could be some snowfall down to low levels tomorrow morning.
In the north, rain showers that were heavy in parts of Auckland this morning have moved into Northland. Some parts of Auckland recorded 4mm to 5mm rainfall in one hour.
"It would have felt very heavy in some parts," Ms Flynn said.
"That trough is now sitting across Northland, so they'll be getting those same showers."
The rain would move further north and away from the country throughout the day. Tonight and tomorrow night temperatures will be getting very low in some parts of the country.Severe frosts were a risk, Ms Flynn said. Monday will see showers for Auckland, Northland and Wairarapa.
