Flooding has closed roads, swamped farmland and cut off communications to parts of Southland today.
Heavy overnight rain has caused the majority of rivers and streams in the region to rise, with some at flood levels.
"Roads are becoming impassable quicker than they can be checked, so we are advising all motorists to stay at home," Southland District Council assets and services group manager Cameron McIntosh said.
"Please only travel if you really have to and exercise extreme caution at all time."
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The Te Anau basin is particularly hard hit, and the Key-Blackmount Rd is the only way to reach Te Anau. However, that road still has water over it and extreme caution is needed. Flood waters are moving into the lower reaches of most Southland rivers following a day of heavy flooding across the region.
By 8pm tonight water levels were dropping steadily in the upper reaches of the Mataura, Aparima, Waiau, and Oreti Rivers as rain eased to steady drizzle in most areas.
Met Service is still forecasting another 15-25mm of rain is likely to fall across Southland overnight but has cancelled its heavy rain warning for the region.
Environment Southland duty incident controller Ken Swinney said that the flood peaks were moving down almost all the major rivers, but council staff and Southland Civil Defence Emergency Management personnel would remain on duty overnight, monitoring river levels and the performance of the flood protection schemes.
Flood models have shown that flows on the Oreti River are likely to equal the maximum that the river's stopbanks are designed to carry. So far, there have been no reports of the river breaching its banks.
The peak flow has already reached Centre Bush and is expected to reach Winton in the early hours of the morning.
Floodwarning staff are also monitoring the Makarewa River, which joins the Oreti in its lower reaches, to assess the impact that both rivers will have on the Taramoa ponding area, close to Invercargill airport. Water is not expected to spill over from the ponding area into the airport at this stage.
Several roads around Te Anau are closed and stormwater is putting some pressure on the pumping systems.
However, the oxidation ponds are safe and water levels in the nearby Upukerora River have dropped since this morning.
Communication with Te Anau has been out since mid-afternoon, when it is believed a telecommunications fibre-optic cable was damaged as a result of the floodwaters.
The phone cable for the area was laid along the Whitestone River Bridge on State Highway 94, which was washed away, a Telecom spokeswoman told NZPA.
Telecommunications contractors were working on the problem and diverting 111 calls to the nearest police station.
Phone calls to local numbers were still getting through, the spokeswoman said.
Phone services were being progressigvely restored this evening.
The Fire Service and Fulton Hogan are trying to drain streets in Winton, with floodwater running into some buildings in the township.
Flood levels in Winton are diminishing due to a decrease in rainfall.
Stormwater drains outside the Senior Citizens' Building in Riverton have been blocked and have caused some flooding and the road is flooded on the north side of the conrner of Main and Lieman Sts in Otautau.
Users of the Lumsden Balfour water supply have been told to both boil and conserve any water they use for at least the next 24 hours because floodwaters have entered the supply system.
More rain is expected to fall until about 6am tomorrow, and the rivers will continue to be monitored by Environment Southland.
Environment Southland said there were no plans to evacuate anybody but civil defence officials were notifying a small number of landowners downstream of Winton whose properties were threatened in the river's last major flood in November 1999.
The Southland Civil Defence Emergency Management Group and police are monitoring the river levels, but there is no state of emergency in Southland.
It is still raining in the upper reaches of most of the major river catchments and the Met Service has issued a heavy rain warning for Northern and Central Southland with a further 40-60mm of rain forecast to fall by 6am tomorrow.
"Provided the Oreti's stopbanks have not been weakened by farming activity or natural deterioration, they should contain the floodwaters," an Environment Southland spokesman said.
Farmland in the Te Anau Basin is already underwater, with extensive damage to fences and other infrastructure.
While Southland copes with steadily rising rivers, helicopters have been flying 120 stranded trampers from huts on the Milford Track amid major flooding in Fiordland National Park.
Continuous heavy rain in the region for the past three days had washed out at least one bridge and threatened other structures, a Department of Conservation spokesman said.
The trampers had spent the last two nights in huts but food was now running low.
DOC programme manager Ross Kerr said the monitoring data for the Clinton and Arthur Rivers on the Milford Track, and Cleddau River in Milford Sound are 'off the scale'.
Meanwhile, two State Highways have been closed in Southland as heavy rain floods rivers. SH 94 between Mossburn and Te Anau and SH 97 between Five Rivers and Mossburn, both in northwestern Southland, have been closed for the rest of the day, NZTA says.
There are warnings in place for SH6 between Kingston and Athol because of surface flooding.
Environment Southland's hydrologists are monitoring the rivers to see what predicted heavy rain will have on already high water levels, a spokesman said.
The Hamiton Burn, a tributary of the Aparima River, has already exceeded its highest recorded level, duty floodwarning officer Karl Erikson said.
The region's flood protection schemes are designed to cope with this level of rain by spilling over their banks in the upper reaches. As a result, widespread flooding in rural areas is predicted.
Roads and bridges are also affected, particularly in the Te Anau area - the Southland District Council will provide updates on local roads and bridges while Opus has details about State Highways.
There had been significant rain in the headwaters right across the region and rivers were rising rapidly, Environment Southland's duty floodwarning officer Karl Erikson said today.
"At 6am the Mataura River was nearly 2 metres above normal at Fairlight in central Otago, and rising at the rate of 140mm an hour.
"The Oreti at Three Kings (between Te Anau and Lumsden) was also approaching 2 metres above normal and rising at 105mm an hour."
Mr Eriksen said that there were no signs of the rain easing.
The Southland Civil Defence Emergency Management Group has been monitoring the situation since early morning and staff are liaising with police across the region, Group Coordinator Neil Cruickshank said.
