Thousands of homes in Southland still have no power, but New Zealand is getting no rest from the wild weather, with more wind and rain bearing down on the country today.

Follow all the latest developments with RNZ's live blog

Forecasters issued widespread warnings for heavy rain, gales and snow across much of the country on Monday.

MetService said a "significant storm" will impact much of New Zealand on Labour Day and Tuesday morning.

MetService has now issued orange and yellow warnings across both islands, and advised travellers to take the conditions seriously, as they head home from the long weekend.

It said an active low-pressure system in the Tasman Sea would cross New Zealand on Monday and Tuesday, affecting almost every part of the country.

Severe weather watches and warnings are now in force, and forecasters warn that conditions may worsen, as the system strengthens.

"An active low-pressure system in the Tasman Sea moves across New Zealand during Labour Day and Tuesday morning, bringing heavy rain and strong winds to many regions, including heavy snow for the Canterbury High Country," MetService said.

Two refrigerated trucks on their side on SH1 outside Balclutha. Photo: RNZ/ Calvin Samuel