A wintry blast expected to hit the country later today could affect travellers on some South Island roads.
MetService is warning the cold front set to move over the lower South Island will bring snow to low levels.
Inland parts of Otago and south Canterbury are under a heavy snow watch with snow levels dropping to 400m, and snow is expected down to 200m for Fiordland and Southland today.
A cold snap coming , but warmer in time for Labour weekend— NIWA Weather (@NiwaWeather) October 9, 2018
Long-range projections are keen on a push of warm air from Australia as we approach the long weekend. Here's hoping! pic.twitter.com/rNEkG4jIWW
MetService issued snowfall warnings for several roads, including the Crown Range and Milford roads where snow showers are expected from mid-afternoon. On Lindis and Haast Pass light snow is expected later this evening.
Trampers have been urged to steer clear of backcountry areas as the front moves northeast.
Warnings are in place for dangerous avalanche conditions in Fiordland, Arthur's Pass, Queenstown and Wanaka.
MetService meteorologist Angus Hines said the cold weather was here to stay for the rest of the week.
He urged people should keep an eye out for road closures in alpine areas.
Snow is predicted to fall down to 300m in Fiordland and inland Southland tonight.
"There's going to be quite cold conditions tonight and that's actually the start of bit of a trend throughout the rest of the week and into the weekend," he said.
"We've got this current bout of cold air but another cold front moving up the South Island on Friday, lowering temperatures even further.
"It will be a nippy night tonight, but people better get used to it for the next couple of nights."
New Zealand Mountain Safety Council communication manager Nick Kingstone said trampers shouldn't assume they are safe while hiking in lower alpine areas.
"People are continuing to go in and really it's about understanding if you're tramping through ... the valley floor, having an idea what's above you," Mr Kingstone said.
"You may not be in avalanche conditions where you are on the valley floor, but actually there may be avalanche paths above you."
The warnings are valid until Thursday.
However, Mr Kingstone said they might be extended depending on changing conditions and trampers should check the online avalanche advisory for updates.
Heavy rain and low-level snow are forecast as a front moves north-east over Fiordland and Southland this morning.
State Highway 94 from Te Anau is likely be closed all of today at this stage.
The weather front producing the snow only reaches upper South Island at midnight, so the North Island is forecast to be mainly fine and dry today.
Good morning New Zealand. A pleasant morning around the country judging by these temperatures. Foehn effect winds helping to lift the temperature in Christchurch. For more on today check out https://t.co/hnwmGxU1gR^MB pic.twitter.com/MkhaeG8uvL— MetService (@MetService) October 9, 2018
Heavy rain is due in the ranges of Buller and Nelson, and the Richmond Range tomorrow.
Later in the week the strong, cold south to southeasterly flow is expected to spread across the North Island, bringing high winds to parts of Wellington and coastal Marlborough, and possible snow above 600m in the central North Island high country and the ranges of Hawkes Bay.
The Desert Road and the Napier to Taupo Road are likely to be affected.