MetService is warning the long weekend may finish with thunderstorms in parts of the country.

Poor weather conditions over the weekend have settled, with only scattered showers expected on Sunday, predominantly in western areas.

But MetService meteorologist Alec Holden said in the North Island, thunderstorms are expected to stretch from southern Manawatū down to northern Wellington.

Meanwhile in the South Island, Holden said afternoon thunderstorms are expected for north Otago and parts of Canterbury High Country.

"Stretching down from southern Manawatū down to northern Wellington, and then over looking at the South Island, a similar sort of story of afternoon thunderstorms for northern Otago and the northern parts of the Canterbury High Country … Hanmer Springs."

There were no official weather warnings or watches in place.

MetService said snow around Aoraki/Mount Cook saw temperatures in the region drop to -3.9C on Monday morning.

A part of State Highway 6 on the South Island's West Coast remained closed due to slips after heavy rain in the region.

Waka Kotahi/New Zealand Transport Agency said the road is closed between the intersection of State Highway 65 at O'Sullivans Bridge and Inangahua.

Waka Kotahi said the road was likely to remain closed all day.

rnz.co.nz