Wild weather: Canterbury rivers rising as heavy rain, strong wind batters South Island

Strong winds and rain have continued across the South Island, with an orange severe weather warning still in place and river levels in mid-Canterbury continuing to rise.

The gales on Monday caused power cuts to hundreds of properties in Canterbury.

Two of the four main power companies were reporting at least 1000 households remained cut off on Tuesday morning, Canterbury Civil Defence Emergency Management group controller Sean Poff said.

"We are expecting further issues right up 'til mid morning."

Council staff were out near Ashburton as river and stream levels were already high and there were with warnings vulnerable areas could flood.

Environment Canterbury said rivers and streams would peak this afternoon but overflow was possible before then.

Strong wind warnings in Canterbury would continue to 9am, and later in the day the effect of heavy rain in the ranges will start to be felt, Poff said.

"The main focus for us will start to shift to the amount of rainfall we've had in the vicinity of the central ranges.

"The main impact of that rainfall won't be realised on peak river flows throughout the region until later today and probably into the night.

"We're actively monitoring our key rivers and have priorities community engagement in those areas assessed at greatest risk."

"We're closely monitoring those critical points."

Ashburton farmer Richard Briden said says severe weather overnight had wreaked havoc on his property.

A number of trees have fallen, and sheep pens and wrought iron had been scattered across his land, he said.

Further south, heavy rain battered parts of the Waitaki District in north Otago, flooding a holiday park in Omarama and several houses in Otematata.

About 50 people were evacuated from Omarama Holiday Park overnight as floodwaters streamed through the campground, owner Irwin Beiboer said, and the water was still flowing in.

Otematata volunteer firefighter Richard Jopson said water had flowing down a couple of streets in Otematata like a stream this morning.

He said about four houses had water going through them and locals worked to save other properties last night.

"One of the residents ... had water lapping at the side of his brand new house and a whole lot of locals banded together and got a digger in and dug a big trench through a paddock, and we managed to divert quite a bit of water."

An elderly couple were among those evacuated and put up at a local pub, he said, and people in neighbouring village of Omarama were also evacuated.

The Waimarama Holiday Park was evacuated as water levels rose in the neighbouring stream.

Waitaki mayor Gary Kircher said the rain hit the towns of Waimarama and Otematata hardest, but it was easing on Tuesday morning.

State Highway 83 from Kurow through to Tarras was closed, as was SH8 Omarama to Twizel and SH6 Haast to Lake Hawea, due either to flooding, slips of fallen trees.

For all the latest road closures check the Waka Kotahi site here.

Westland and Buller have also been getting heavy rain.

In 12 hours overnight, 200mm of rain fell at Aoraki Mt Cook and there were wind gusts of up to 130 km/h.