A Golden Bay commune has been cut off from the world after heavy rains caused a river to change its course.
The wet weather sweeping the country has again hit hardest in the Nelson and Tasman regions, just weeks after the heaviest deluge in 50 years closed roads and made dozens of homes uninhabitable in the area.
Nelson Tasman Civil Defence controller Jim Frater said the heavy rains had forced the Wainui River in Golden Bay to carve a new course.
"It's taken out a big chunk of the road and gone about 900m down through the Robertson Farm, which sustained a substantial amount of damage including, I believe, wiping out the cowshed in the last event,'' he told APNZ.
Mr Frater said while it was still possible to access the area with care, the road damage had "basically isolated'' both the farm and the nearby Tui Community, a commune founded in the early 1980s.
The 50-hectare commune, which describes itself as an "intentional community'', is home to about 40 people.
Mr Frater said the residents were resilient enough to have adequate supplies for about a week.
"But obviously we'll be keeping a close eye on that.''
In the Pohara Valley, three homes were evacuated and the Civil Defence emergency operations centre sprang into action after heavy downpours caused localised flooding last night.
"Police were going door-to-door and checking with people, making sure they're okay, and contractors were out checking drains and so forth,'' Mr Frater said.
The Pohara camping ground suffered minor flooding, forcing staff to move campers and set up sandbags.
Mr Frater said the centre called it a night after rain eased in Golden Bay by 1.30am.
Contractors across the Nelson and Tasman regions have been assessing damage since first light, with most reports of only minor localised slips or flooding.
In Nelson, the Maitai River reached its first alarm level at 6am but was dropping again, Mr Frater said.
"It's not expected to get to flood levels, but the reason we're interested in that is there's a large amount of teenage revellers at the Maitai camping ground.
"They're currently very wet, but apparently happy.''
Mr Frater said authorities were monitoring the river but it did not appear the camping ground would be cut off.
Cable Bay Rd, Iwa Rd and Moana Ave were closed yesterday as a precaution. They were not expected to reopen until later today at the earliest.
The wet weather has also been causing havoc in Waikato, with police called to nine crashes between 7am and 9am.
District road policing manager Inspector Leo Tooman said smashes had been reported in Taupiri, Horotiu, Kopu, Kopu-Hikuai, Whitianga, Whiritoa and Whangamata.
"It really is a case of cars falling off the road as drivers lose control in very slippery conditions and the only solution is to slow down, even if that means travelling at 70 km/h in the wet,'' he said.
"Drivers need to realise 100 km/h is a limit not a target.''
Mr Tooman said drivers on holiday highways heeded warnings yesterday but were less responsive today.
"Yesterday we were very pleased with drivers adjusting their speeds on both SH25 and SH25A up and down the Coromandel but today it seems a lot of our warnings are falling on deaf ears.''
Another problem was cyclists wearing dark clothing in wet conditions, making it very difficult for other road users to see them.
The MetService is forecasting bursts of heavy rain for many areas across the country, with the biggest downpours predicted for Taranaki, the central North Island high country and Bay of Plenty.
Heavy rain is also forecast for Nelson and northern Marlborough, along with Wellington and Kapiti Coast today.
Significant rain, with heavy falls, was also expected to affect Wairarapa, Manawatu and Wanganui from later today and into tomorrow as a southerly change converges with warmer northerlies and becomes slow moving for a time.
Isolated thunderstorms with localised downpours were possible tomorrow afternoon in central areas of the North Island.
Meanwhile, a severe weather warning has placed a large question mark over New Year's Eve plans at Mt Maunganui.
Heavy rain, forecast from today to Sunday, has prompted Tauranga City Council to reconsider its plans.
A decision is expected today on whether the council will erect a second stage to go along with a larger main stage as part of Tauranga's main New Year's Eve Event.
The fate of the main stage will not be decided until tomorrow.
Council spokeswoman Alison Clifford said a Plan B was in the works but it was hard to say what would be happening until there was more certainty with the weather.
"We are kind of on stand-by. If we can't have the first stage but still have the second stage, we will still go ahead.''
Ms Clifford said this would mean a smaller range of options for partygoers but entertainment would still be provided.
"It just limits us to the stage in one area. Hopefully, the weather plays ball.''
Traditionally the council's New Year's Eve Event attracts thousands.
The MetService says up to 200mm of rain could fall throughout the coastal hills and Kaimai Ranges in the 48 hours from 3am today.
- Matthew Backhouse and Hana Garrett-Walker of APNZ
