The Milford Road is closed and a car is stuck on the Crown Range Road due to heavy snow this afternoon.
The Queenstown Lakes District Council said the car was stuck near the summit lookout and this was causing further delays to traffic. It advised road users to allow for this or use the Kawarau Gorge.
It tweeted just after 2.30pm it was snowing heavily on the Crown Range Rd and chains needed to be used.
Downer this afternoon said the Milford Road (SH94) would close overnight from Hollyford road junction to the chasm. Snow was forecast down to 700m.
The road was likely to reopen by 10am tomorrow, but ''significant snow'' was forecast down to low level on Thursday (40cm-60cm expected in the Homer Tunnel area), which could mean an all-day closure. Snow was also forecast for Saturday.
The chilly blast was also forecast to bring snow down to 400m in the south of the South Island, and many alpine roads were subject to road snow warnings through to tonight including Arthur's Pass (SH73), Lindis Pass (SH8), Crown Range road, and Dunedin's Northern Motorway (SH1).
Flooding in Otago, Southland
The New Zealand Transport Agency has issued two flooding warnings for inland Otago. Road users are asked to take care and drive to the conditions.
Southern District Police said there was reported flooding in various locations on State Highway 6 between Cromwell and Makarora this afternoon.
State Highway 8 from Omarama to Cromwell (Lindis Pass) was under caution due to surface flooding "at various locations through this area".
In Southland, roads in and around the Mossburn area have been affected by flooding this afternoon, the district council advised.
They were: Dyer Rd, Felton Rd, Gallagher Rd, Dunrobin Valley Rd and Wreys Bush Mossburn Rd. Flooding signs are in place.
The rain also has caused surface flooding in parts of Wanaka. An estimated 21mm of rain has fallen since 6am today and by early afternoon showed no sign of stopping.
The flooding warnings come as a belt of wild weather was set to bring heavy rain, gale-force winds, thunderstorms and snow to parts of the country.
MetService said a "disturbed weather pattern" was over the country this week.
A cold front was making its way on to the bottom of the South Island this morning, bringing heavy rain and strong winds.
The heaviest rain was expected in Fiordland, Westland south of Otira, and the headwaters of the Otago and Canterbury lakes and rivers, where 100mm-150mm could fall.
Over the South tomorrow there was a moderate risk of thunderstorms about Fiordland and Southland before dawn. These could bring brief heavy rain, hail and snow to 400m-500m.
A very unstable west to southwest flow would cover northern and central New Zealand tomorrow, bringing more heavy showers, thunderstorms and hail.