Huge rains swamp South

The Hollyford River is among the areas hit. Photo / NZTA

Trampers were evacuated by air, phonelines cut and bridges washed out last night as rain and heavy flooding threatened to inundate areas of the South Island.

Residential phonelines in Te Anau and Fiordland in the deep south have been knocked out, police say.

The area has been inundated with rain for three days, forcing road closures and the evacuation of more than 100 trampers.

The MetService yesterday warned more heavy rain was on the way in northwest Nelson, Westland, Fiordland, and the Canterbury and Otago headwaters overnight and today.

People within these areas of the South Island, especially hunters and trampers in the mountains and river users elsewhere, were advised to take extra care around rivers and streams over the next few days.

The heaviest rain was expected between Otira, 160km northwest of Christchurch, and George Sound in Fiordland, where 200mm to 350mm was possible in some places yesterday and today, while up to 150mm was likely to spill over the main divide into the Canterbury and Otago headwaters.

This rain would fall in addition to the significant amounts over the past two days, and bring further rises in river and stream levels in Westland and Fiordland, and also to the rivers of Canterbury and Otago feeding from the Southern Alps, the MetService said.

Department of Conservation programme manager Ross Kerr said 120 trampers on the Milford Track had been holed up in three huts for the past two nights, but diminishing food supplies meant evacuations were necessary.

Rainfall measuring 793mm had doused the Fiordland National Park and Southland district since Saturday night and there was no sign of it letting up.

The trampers were being flown out of the area and being delivered to the head of Lake Te Anau, where boats would ferry them to the town.

"We'd expect the first boatload back to Te Anau probably sometime after 3pm," Mr Kerr said. The last two tramping parties for the season had been cancelled, he said.

Environment Southland said flooding had caused extensive damage to fences and other infrastructure on farms in the Te Anau Basin, while river levels continued to rise across Southland.

The Oreti River may reach the same levels as in November 1999, which caused widespread flooding of farms and roads. The river was expected to be contained within the stopbanking system but areas which were flooded in 1999 could expect to be flooded again.

Civil defence staff were contacting some landowners south of Winton to advise that spillover could threaten their properties.

Environment Southland's hydrologists were monitoring the rivers and modelling the impact that further predicted heavy rain would have on already high water levels.

Catchment manager Noel Hinton said the peak was expected to pass through Winton about 2am overnight and reach Wallacetown, just upstream of Invercargill, between 10am and midday today.

Communities further upstream were not expected to be affected.

Invercargill Airport, which is just downstream from a ponding area expected to fill by noon, would not be affected.

The Hamiton Burn, a tributary of the Aparima River, had already exceeded its highest recorded level, duty flood warning officer Karl Erikson said.

However, he said, there were no concerns for the Southland community of Otautau at this stage.

The Aparima, Mataura and Makarewa rivers should have ample stopbanking capacity and would not pose any threat to urban communities, but widespread flooding of farmland was expected.

The flooding prompted the Southland civil defence emergency management group to advise motorists to avoid non-essential travel.

- NZPA