Auckland is being hammered by rain tonight and several people are fighting for their lives following a spate of serious crashes around the country.
The incidents follow a brutal weekend on the roads after five people lost their lives in fatal accidents from Friday night to yesterday evening.
Meanwhile, a complex low-pressure weather system is lashing out over the North Island tonight with torrential rain resulting in surface flooding.
In Christchurch, seven people have been injured in a nasty multi-vehicle crash in which an eyewitness said a vehicle became airborne before smashing into another car.
Emergency services said three cars crashed at the intersection of Ferry Rd and Aldwins Rd in Waltham, Christchurch earlier this evening.
"A car was going down Aldwins Rd to Ensor Rd, so he's heading out of New Brighton," the witness told the Herald.
"He has gone through a light, he became airborne, he took out one car as he went over the intersection which forced him onto on-coming traffic where he's taken the door of a driver's vehicle."
St John reported the seven people were transported to Christchurch Hospital in an array of different conditions.
Four people were serious, one person had moderate injuries and two others received minor injuries.
Elsewhere, a child is believed to have been critically injured in a crash on Massey Rd in Mangere shortly after 8.15pm.
St John reported four emergency vehicles attended the incident and treated one patient who was transported to Starship Hospital.
Signs above Auckland's motorways are urging drivers to be cautious of surface flooding following heavy rain tonightvv
A motorist said the rain was bucketing down and driving conditions on the Northwestern Motorway were treacherous around 10.20pm.
"The rain is hammering down. Visibility is poor and some of the surface flooding is unbelievable. If you don't need to drive I'd stay off the roads," he said.
Severe weather watches have been issued for five regions tonight.
MetService said Auckland can expect periods of rain, heavy at times with isolated thunderstorms from 8pm today until 7am tomorrow.
Those in the Waikato can expect similar weather conditions, except rain can be expected until 8am tomorrow.
A heavy rain watch now includes the Tararua District, the Tararua Ranges, Wairarapa, and eastern Marlborough, MetService said.
There have been a spate of other serious crashes throughout New Zealand today, following the launch of the official road toll period at 4pm.
A car rolled near the intersection of Arapuni Rd and Johnson Rd in south Waikato earlier this evening around 7 o'clock.
St John reports a helicopter was dispatched to the scene and was transported to Waikato Hospital after sustaining serious injuries.
Elsewhere, police were called to a crash near the intersection of Rapanui Rd and Erin Rd shortly before 7pm near Whanganui.
One car went into a ditch but no one was reported as trapped, police said.
Other accidents today included three separate crashes in the South Island, where firefighters were called to extricate people from cars with cutting gear.
The first incident was in Geraldine this morning, followed by a second crash in Ashburton, and a third at Thompson's Track, also near Ashburton, this afternoon.
There were also reports of a crash in Christchurch requiring fire attendance, which was ongoing.
Bad weather resulted in the left-hand lane of the Southwestern Motorway heading westbound being blocked after a car spun-out around 5pm.
Pictures from the scene show a police car and an ambulance on the scene where a white car has ended up sideways near the barrier wall.
None of those involved were seriously injured, but FENZ spokesman Riwai Grace said it was "insane" to see drivers not being patient or driving to the conditions.
"We have been to a phenomenal amount of callouts already. The last three days across the country we've been inundated with crashes," he said.
Grace urged motorists to think of families and friends when on the roads and asked people to get to their destination safely.
"It's not a nice way to start Christmas."
In the North Island, two Westpac Rescue Helicopters were sent to a single vehicle crash at Waiuku around 2.30pm, on Awhitu Rd.
One person was in a critical condition, police said, while the other person had serious injuries. Both were taken to hospital.
The Serious Crash Unit had been advised.
Emergency services were also responding to a crash near Matamata, where a car was stuck between two trees; and another in Maungakaramea in Northland where a car had rolled.
The official holiday road toll started at 4pm today, and runs through to 6am on Thursday, January 3.
Police started a lower speed tolerance period on Saturday, meaning anyone travelling at more than 4km/h over the speed limit will be ticketed.