NZ braces for severe weather as rain threatens flooding

Heavy rain and strong winds have lashed parts of New Zealand as a cold front moved east across the country, and authorities warn conditions could worsen over the next 24 hours, triggering floods and landslides.

The northern regions of both the South Island and North Island of the country could be severely affected by the wild weather, the country's weather bureau said on Friday.

New Zealand's MetService said the wind would pick up from Friday afternoon, with gusts of up to 120km/h forecast for some regions. There could be severe thunderstorms later on Friday, MetService's Heather Keats said.

A state of local emergency has been declared for the Nelson Tasman region for the second time in as many months with officials warning that rivers could rise quickly because the ground remains wet following floods at the end of last month.

Motorists have been urged to stay off the roads, while the authorities have asked residents in the Nelson Tasman region to evacuate their homes if they feel unsafe.

"In these conditions, it's just not worth the risk," the Tasman District Council said in a post on social media.

"We have a number of roads already closed ... and we're expecting more closures to happen in the coming hours due to tree falls from heavy winds and significant surface flooding."