Freezing weather is due to hit the South Island and parts of the North Island, WeatherWatch warns.
Snow is due to fall to low levels in Southland and Otago today and tomorrow, which will see temperatures plummet, analyst Richard Green said.
"It'll be close to the freezing mark for some places in the south tomorrow and Tuesday."
"Icy winds combined with sleety snow showers will make roads marginal at best in some cases, possibly on either or both days."
West Coasters are also seeing wintry conditions and falling temperatures, Mr Green said.
Heavy showers and some thunderstorms were predicted to settle over Canterbury later today or tomorrow.
The air could be cold enough for snow to fall at sea level, said weather analyst Aaron Wilkinson.
"It will still be fairly coastal, although there's a chance showers could move a little more inland now on Tuesday afternoon (or) evening."
There was also a chance of snow flurries up to 30-50 kilometres west of Christchurch.
"One thing is that there could be a few sunny spells about on Tuesday morning and there is a chance that this may lift the temperature a little," Mr Wilkinson said.
By the end of Tuesday, there could be one or two centimetres of snow settled, he said.
Dunedin appeared to be in line for higher snow amounts overall and other areas exposed to the south across Otago and Southland could also see some reasonable snow levels, he said.
Meanwhile, the North Island doesn't miss out on the chill, with higher parts of the island possibly getting flurries over the next couple of days.