Heavy rain, slips and floodwaters have forced the closure of three key roads on the South Island, effectively cutting it in half.

A state of emergency was issued in the Timaru District on Saturday after both State Highway 1 and the inland route on State Highway 72 at Arundel near Geraldine in South Canterbury were shut after major flooding of the Rangitata River.

Slips have also forced the closure of much of State Highway 6 on the West Coast, meaning there are no main roads linking the north and south of the island.

Scores of people have been left stranded, forced to search for emergency accommodation in motels and campsites or to stay with relatives, including one man desperate to get home to his heavily pregnant wife in Australia.

READ MORE:

* Live: Flooding devastation in weekend of heavy rain and thunderstorms

* Rangitata Bridge to remain closed for at least next 36 hours

* Stranded travellers and residents hunker down for the night

* Braided river chicks and eggs suffer after major deluge in the Rangitata River

Civil Defence Minister Peeni Henare will travel to the West Coast on Sunday to meet Westland mayor Bruce Smith, speak with affected locals and assess how the Government can help with recovery efforts.

JOHN BISSET/STUFF Heavy rain has caused Canterbury's Rangitata River to burst its banks, forcing the closure of two main highways on the South Island.

The Rangitata Bridge at SH1 and the bridge at Arundel on SH72 will remain closed for at least the next 36 hours after the roads were badly damaged, while communities along SH6 between Harihari and Haast – including Franz Josef and Fox townships – are likely to be cut off for a number of days, NZ Transport Agency (NZTA) said.

NZTA system manager Pete Connors said: "Until the waters recede, we cannot get in to do the repairs needed.

"We have crews and machinery ready to reinstate the highway and ensure it is safe for all road users once the flood waters from the river's tributaries have been contained back into their main flow."

Problems have been compounded by Spark's landline, broadband and mobile services also temporarily being down.

JOHN BISSET/STUFF Flooding has cut people off, here at the intersection of State Highway 1 and State Highway 79 to Geraldine.

Eftpos were also affected, leaving some businesses in Timaru and Geraldine unable to take card transactions and people queuing at ATM machines to get cash.

Local Government New Zealand (LGNZ) said the issue highlighted the urgent need for councils and the Government to ramp up investment in New Zealand's river management and flood protection schemes.

"Flooding is New Zealand's most common natural hazard, one that is exacerbated by climate change induced storm events that are hitting us more frequently and with more ferocity," said LGNZ President Dave Cull.

"Our river management and flood protection schemes have largely performed well over the last three decades, but as this weekend's storm and the 2017 Edgecumbe floods have shown we need to ramp up investment if we are to protect our communities and our economy now and in the future."

BEJON HASWELL/ STUFF Scores of people have been forced to sit out the flooding at motels and holiday parks, among them Lesley Washbourne of Leeston and her family who are stuck at the Geraldine Top 10 Holiday park after coming down for the town's Christmas Parade.

Dozens of people have been cut off from their homes, stranded either south of the Rangitata River or on its north side.

Steve Jones flew from Sydney with his daughter Chloe and sister Stacey on Thursday to celebrate his grandfather's 90th birthday at a family party on Saturday near Oamaru.

He is due to fly back to Australia from Christchurch early on Monday to be with his heavily-pregnant wife Kacie, but is resigned to not getting home until later in the week.

"We had a huge family reunion, close to 50 of us from all over New Zealand, and about a dozen of us who came from Australia," he said.

"My wife is heavily pregnant and as of tomorrow is full term, so she is a little anxious about the situation if the baby was to come if I wasn't there.

"We don't think the baby is coming tomorrow, but it could be any time. My wife understands the situation and that there is not much I can do about it."

Supplied Steve Jones, right, is stuck in Oamaru and unable to get back to his heavily pregnant wife in Sydney after flying to New Zealand on Thursday for his grandfather's 90th birthday.

Stuck in Oamaru, Jones has rebooked a flight for Wednesday afternoon but hopes he can get to Christchurch earlier.

"If the worst comes to the worst my aunt's neighbour has a helicopter being used to transport people to Christchurch so they can make flights, so that is always an option.

In Timaru, dozens of tourists were among at least 80 people forced to find shelter through the Southern Trust Event Centre since Saturday evening, which the local civil defence group used a base to help stranded people.

Some stayed at the centre overnight, while others used it to find accommodation.

Civil defence manager Leah Stringer said: "We started off with a bus of Korean tourists, and then we had some from Germany and Australia.

JOHN BISSET/STUFF Rangitata, about 45km north of Timaru, was put into a state of emergency in December 2019 as the Rangitata River burst its banks following significant rainfall that led to widespread flooding and slips, considered a one in 20 year event.

"Everyone has been very understanding, but it's been a lot of work. I got about an hour-and-a-half's sleep last night."

Jawad Masumi was part of an extended family of 29 who arrived in the centre just before midnight.

The group had been on the way back to Christchurch after attending a cousin's graduation ceremony in Dunedin, but were forced to stop because of the flooding.

"It's frustrating because we all have jobs to get back to. We'll be looking to stay in a motel tonight, but the civil defence people have been really helpful."

The owner of Stay Timaru on Elizabeth St and Hibernian Studio Apartments on Latter St, who declined to be named, has been offering showers, couches, and parking spaces to those displaced by the flooding.

BEJON HASWELL/ STUFF Civil Defence staff in Timaru have been busy, including helping stranded tourists find accommodation.

"A significant amount of supplies are going down but we're getting more in. We're really keen to help," he said. "It's very much battle stations at the moment."

Workers at the Top 10 Motor Camp in Geraldine reported the place was "heaving" with people, as many tourists and commuters were blocked from travelling further north on Sunday.

Timaru District Council warned that the town is "extremely busy", causing significant pressure on facilities.

Eftpos and cash machines were not working as of 1pm on Sunday as data networks are down.

People stranded at the town's motor camp were upbeat about their situation, however.



JOHN BISSET/STUFF The Rangitata River has seen its worst flooding in around 20 years.

Lesley Washbourne of Leeston, who travelled with her family for the Geraldine Christmas parade, is unable to get into work until Tuesday.



"You can't do much about what mother nature throws at you," she said.



Australian tourists Luke and Sarah Muttdon had hoped to get up to Christchurch on Sunday but had resigned themselves to staying in the South Canterbury town.



"It's not all bad, we're lucky that we didn't have a flight to catch. We'll just have to explore around Geraldine."

A Facebook page, Geraldine Homestay Network, has been set up to help travellers who have been turned away at Orari Bridge on their way up the South Island, who are in need of accommodation.

Most of the people coming through were international visitors who were not familiar with the landscape, Go Geraldine promotions coordinator Janena Adams said.

"Some of the people are a little distressed."

BEJON HASWELL/ STUFF A Spark outage meant Eftpos machines were unable to be used, leaving queues outside ATM machines in Geraldine.

While residents near the Rangitata River have also been affected by the flooding, some have been prepared for such an event.

Rangitata resident Russell Brodie, whose family have lived in the area for about 100 years, has a flood channel running alongside his home and said he had enough supplies to outlast the flood.

"Everybody has to be pretty self-sufficient, though some would have had to evacuate with water through their house."

Flood channels put in during the 1950s have been removed as land has since been developed, meaning water ends up in the wrong places.

"We'll see what comes out of this," he said.