Snow damage has left hundreds without power in Central Otago.

About 300 households remained without power in Clarks Junction, Hindon, Redbank, Ranfurly, Waipiata-Kyeburn and Middlemarch-Bald Hill, PowerNet said in a social media update at 4pm.

That number could "potentially increase" overnight, the update said.

PowerNet said its team had been patrolling lines today, including in the air.

It had found more than 30 broken poles and more than 20 broken crossarms.

Teams and equipment from Invercargill, Gore, Balclutha, Ranfurly and Palmerston were working to restore power.

A generator was on the way for the Clarks Junction-Hindon line, which it said was the "most impacted".

However, it added it could not guarantee the power be back on tonight.

Safety of its team was a priority, as conditions remained treacherous.

Care urged on roads

NZTA was urging for caution on roads across the South Island as more snow, heavy rain or ice could make for treacherous driving conditions overnight.

It added there would likely be state highway closures into tomorrow.

The heavy rainfall and melting snow meant there was a risk of ice build-up, and crews would be laying grit and anti-ice agents on highways to assist vehicle traction.

While heavy rain and snow had eased in Otago, snow continued to fall in the Mackenzie Basin this evening and State Highway 8 Fairlie to Lake Pukaki remained closed.

MetService was warning inland Canterbury north to the top of the South Island could be in line for rain and snow overnight and tomorrow.

A red heavy rain warning was in place for Canterbury between Ward and Hanmer Springs, and southeast of Awatere Valley, including the Kaikoura Range.

This red level of warning carries the risk of a threat to life from dangerous river conditions, significant flooding, slips and impassable roads, NZTA said.

Strong winds remained a threat on the West Coast, where SH6 had been closed between Whataroa and Harihari.

- Allied Media