Heavy rain is set to hit the west of the North Island in the next few hours, bringing with it the possibility of thunderstorms, hail and strong winds.
The New Zealand Transport Agency is warning commuters to take extra care on their way home this evening.
MetService forecaster Hordur Thordarson said there was a good possibility that thunderstorms would hit the west of the North Island from Taranaki to Northland in the next one or two hours.
Strong winds of about 100km/h were likely, with a low risk of damaging gusts of up to 110km/h.
A moderate to low risk of storms was forecast for eastern regions.
The slippery weather has seen several crashes causing delays on Auckland's roads.
The Northern Motorway city bound was blocked earlier due to a crash on the left lane after Constellation Dr.
The crash has now been cleared, but traffic is backed up to Greville Rd.
And a crash on State Highway 1, northbound, near Bawden Rd in Dairy Flat is also causing delays in the area.
Motorists are advised by NZTA to expect delays.
Earlier today, MetService duty forecaster Karl Loots said a moderate to low risk of storms was forecast for eastern regions.
Another squally evening with gusts overnight was in store for parts of the Auckland region, including Helensville, Piha, Muriwai, the Waitakeres, Awhitu and Waiuku.
This morning's motorway chaos began about 6am with a single-vehicle crash on Auckland's Southern Motorway. It closed the Symonds St off-ramp for about an hour.
At 7am, a two-vehicle crash just after the Onewa off-ramp delayed traffic on Auckland's Northern Motorway.
Shortly after, a truck broke down on the Auckland Harbour Bridge blocking the right lane of northbound traffic for an hour and a half.
Soon after it was cleared, a five-car nose-to-tail crash partially blocked the left lane northbound on the Mangere Bridge of the Southwestern Motorway. Traffic was delayed for two hours.
Meanwhile, fine weather is expected to span across most of the South Island today - a welcome change from snow and heavy rain in the past few days.
Mr Loots, of MetService, said there would be a few showers peppering Canterbury today.
A fast moving front would also bring rain to upper regions of the island including Nelson, Buller and Marlborough this afternoon.
But snow showers have eased at the Lewis Pass, Arthur's Pass and Porters Pass.
The Lindis Pass and the Pomahaka Bridge on State Highway 90, which were closed due to weather conditions yesterday, have been reopened this morning.
MetService said some snow showers were expected at Arthur's Pass overnight, with snow above 800 metres possible.
Porters Pass could get brief snow showers overnight, which could cause a small amount of snow to fall on the summit of the road.
NZTA is, however, advising motorists to take extra care on the Lindis Pass as ice on the road is still an issue. Grit has been applied.
Care is also required on State Highway 94 between Gore and Lumsden because of surface flooding.
There is also flooding on State Highway 16 between Nokomai and Fairlight, and snow and ice on State Highway 8 between Omarama and Cromwell.
State Highway 6 between Haast and Makarora is down to one lane as storm damage is repaired and cleaned up.
WeatherWatch is expecting the stormy and disruptive weather to ease by Thursday. However, there would still be unsettled weather for much of the country.
Mt Taranaki has had a dump of snow during the week.
Ian McAlpine, of Mt Taranaki Guided Tours, said inexperienced trampers should stay off the mountain, as winter conditions brought short days, icy slopes and strong winds.
He suggested doing another trek at Taranaki Egmost National Park instead, including the Pouakai Circuit and Pouakai Crossing.
"There are some beautiful places visit without trying to climb to the mountain's summit when crampons and ice-axes are required."
MAIN CENTRES OUTLOOK
Today: Few showers, evening rain with a chance of thunder. Northwest winds. High 21C. Wednesday: Periods of rain, possibly heavy. Strong southwest change. High 20C.
Few showers, evening rain with a chance of thunder. Northwest winds. High 20C.
Periods of rain, possibly heavy. Strong southwest change. High 18C.
Few showers, evening rain with a chance of thunder. Northwest winds. High 18C.
Rain, possibly heavy, and strong northwest winds, easing in the evening. High 17C.
Few showers, rain from late afternoon with a chance of thunder. Northwest winds. High 18C.
Rain with a chance of thunder. Rain eases in the evening with a southwest change. High 16C.
Rain from late afternoon, some possibly heavy. Northerly strengthens. High 16C.
Rain clearing in the afternoon before becoming fine. Gale northwest winds ease. High 15C.
Early showers then fine. North east develops. High 11C.
High cloud. Northeast for a time. High 12C.
Chance early shower, otherwise fine. Northerly develops. High 11C.
Increasing high cloud. Northerlies. High 12C.