MetService meteorologist Kyle Lee said the same system would hit New Zealand on Wednesday.
Currently sitting off Australia's southeast coast, it was set to bring cold southerlies to Tasmania and Victoria before moving inland through New South Wales and out on to the Tasman Sea where it would strengthen tomorrow.
"It should gather momentum about midnight tomorrow and then looks like heading to New Zealand on Wednesday," Lee said.
MetService may look at putting out severe weather watches tomorrow, he said.
It means Auckland residents should make the most of the chilly but fine weather today as sunny skies are expected along with a high of 14C.
Cloudy skies should then take over tomorrow along with a high of 17C and chance of showers in the evening before the wild weather and possible heavy rain strikes on Wednesday and Thursday. Strong winds and possible gales in exposed areas are also expected.
Elsewhere, Wellington can expect clear skies and a high of 13C today, before a few afternoon showers and top of 15C tomorrow.
Gale force winds should then blow in on Thursday along with possible heavy falls and a top of 12C on Wednesday.
Christchurch is tipped to have a mostly fine top of 11C today before dropping to minus 2C overnight and a high of 8C tomorrow with a few showers. Showers are also expected on Wednesday with a top of 9C.
MetService is tipping Wednesday's heaviest falls to hit the mountain ranges from Taranaki and the Kāpiti Coast to the Central Plateau and Bay of Plenty.
In the South Island, most regions should be free of rain on Wednesday before the entire southern and western coasts are blanketed in falls on Thursday.
But that won't mark the end of the bad weather.
Fellow forecaster WeatherWatch said a second southerly blast would then build on Thursday before surging "once again up and over the North Island" on Friday.
It means Kiwis can expect a bleak wintry and windy end to the week that will again produce heavy snowfall in the mountains and possible power cuts in some regions although winds are tipped to generally stay "below damaging thresholds".
Snow warnings are now in place for mountain roads, including through Arthur's, Porters and Lindis passes and the Crown Range and Milford Rds.
However, a high pressure system should then roll in next weekend and gradually "calm things down", WeatherWatch said.
The stormy outlook comes as winter finally hit New Zealand late last week after May had been dominated by settled and fine weather.
In the lead-up to the Queen's Birthday weekend, heavy rain, thunderstorms, hail and a chilly polar blast hit much of the country.
It brought large dumps of snow and sent temperatures plunging by up to 10C, while the South Island's West Coast was deluged with more than 500mm of rainfall at some weather stations.
"What made the weather so interesting is that the low pressure sourced its wind from as far south as Antarctica, dropping temperatures and allowing snow to lower to 200 metres in parts of the South Island," MetService's Lee said.
"At higher levels, we had reports from some South Island ski fields who received around half a metre of snow which is welcome news ahead of the start of the ski season."
