More rain for parts of South Island drenched by yesterday's wild weather

It's a wet and miserable day in Central Otago with flooding taking over Ranfurly Holiday Park. Photo / Supplied

Parts of the South Island already drenched by yesterday's deluge are in for more rain today.

Thunderstorms in parts of the lower South Island sparked flooding and slips that closed state highways and caused havoc for holidaymakers.

Heavy rain that hit North Otago, Dunedin and Clutha yesterday was expected to continue overnight with heavy, possibly thundery showers forecast for Southland and Dunedin today.

The stormy weather is set to ease tomorrow, with a mostly cloudy day forecast and a few showers in the afternoon or evening for Southland and Dunedin.

Dunedin City Council opened two sandbag stations for residents yesterday, as the city knuckled down for a night of wild weather.

Hundreds of people were also left stranded at the Whare Flat Folk Festival, northwest of Dunedin, after flooding closed the road in.

Michaela Cox, whose 20-year-old daughter Stella is attending the festival, said she had tried to pick her up yesterday but couldn't get through as the roads were closed.

"I'm a bit worried but there's nothing I can currently do. I've been checking the news and weather updates regularly and hoping that Stella's tent is not soaking wet," she said.

"Apparently the Scout Hall is open so I'm imagining everyone hanging out in there eating and listening to live music ... best case scenario!"

Campers in parts of the lower South Island were warned to move to higher ground, while those in Otago planning to start the commute home were urged to delay their travel until today.

Emergency Management Otago asked holidaymakers in Otago to stay put last night as floodwaters covered roads and closed four main state highways with slips and washouts.

Meanwhile, boaties using Lake Aviemore were warned about large submerged logs and debris after a heavy downpour in the Canterbury high country pushed debris into the water.

A heavy rain watch was in place for the Canterbury high country yesterday, while MetService forecasts more rain and showers with the possibility of thunderstorms and hail south of Lake Coleridge from this afternoon.