Ashburton has seen 71mm of rain since 8pm, Christchurch is at 65mm and Timaru 46mm.
Heavy Rain Warnings have been issued for Eastern Marlborough and Canterbury and a Heavy Rain Watch for North Otago until 3am tomorrow.
The heavy rain is a result of a slow-moving low east of New Zealand that is continuing to direct a moist easterly flow over the South Island.
The region has suffered widespread surface flooding overnight, with roads in Ohoka, Rangiora and Cust some of the worst affected.
Flood signs are being put out, but Waimakariri District Council said driving conditions were hazardous and people should stay off the roads if possible.
Canterbury Regional Council said rivers were already up after heavy rain last night and warned some might flood today as rain continues."Our main rivers of focus are the Eyre, Cust, Cam, Ohoka. Flows are increasing towards the design capacity of these rivers and Civil Defence Emergency Management groups are monitoring these areas carefully," the council said.
"The Ashley river is rising but is not expected to reach levels which threaten the flood protection scheme.
"The Okuku river may have localised out of river flooding, likely in the same areas that have seen these effects since 2021."
Significant surface flooding and ponding was occurring throughout the region, the council said.
Niwa is reporting that Akaroa in Banks Peninsula has provisionally had its wettest day on record, with 198.mm of rain falling from 9am yesterday to 9am this morning.
It said numerous locations in Canterbury had received more than a month’s worth of rain already, with more still to come.
Rangiora has had 94.4mm of rain, Wakanui 78.2 mm and Winchmore 76.2 mm.
Flooding has closed Tramway Road in Ashburton between Lochheads Rd to Thompsons Track, and also from Ashburton Forks to Valetta.
The Ashburton Civil Defence Emergency Management is asking people to take extreme care on the roads and avoid unnecessary travel.Flood warnings have also been issued by Environment Canterbury.
Ashburton District Council is warning that waters can rise extremely fast and is asking people to please avoid the area.
The council is reporting widespread surface flooding across the district with multiple closures in place.
"Please avoid unnecessary travel and do not drive through flooding," it said in a post on Facebook.
Taylors and Bowyers Streams are high and rising, and although the North and South branches of the Ashburton River have not yet risen likely due to snow at the top of the catchment, they are expected to rise later today.
Eastern Marlborough and Canterbury about and north of Cheviot can expect another 70 to 100mm of rain during this period. Rain was expected to fall as snow above 300 or 400 metres at first, but the snow level is likely to rise to above 1000 metres later this morning.
Another 60 to 90 mm of rain is expected to fall in Canterbury south of Cheviot. Snow was expected above 600 metres in MacKenzie Basin at first, with the snow level rising above 1000 metres later this morning.
MetService said from Tuesday through to early Thursday, a cold showery west to southwest flow would affect New Zealand.
On Wednesday, southwest gales are possible about coastal parts of the North Island and these could become severe about Northland and Auckland. Later on Thursday and Friday, a ridge of high pressure was likely to spread across the country, according to Met Service.
Several roads are closed in the South Island due to flooding and heavy snow.
South of Christchurch, on Banks Peninsula, State Highway 75 is closed between Birdlings Flat and Cooptown, due to severe weather conditions.
In South Canterbury, State Highway 8 is closed between Fairlie and Twizel, due to heavy snow.
Anyone who feels their home is at risk of being flooded should call 111 immediately.
Residents needing help to evacuate, or who live on a street where drains have overflowed, should contact their local council.
- RNZ/NZ Herald
