A Civil Defence Emergency has been declared in Nelson and Police are advising people to stay home unless it is absolutely essential tonight.
Several roads are closed and many others are affected by flooding and slips as the region is deluged with rain.
Police incident controller Inspector Ross Lienert said a number of houses had been affected by slips and Police are advising people to call immediately if they think their property is affected by slippage.
"Properties affected by slippage could be life-threatening and we want people to call," Inspector Lienert said.
River levels in the area are currently high but water levels are stable, however Police and other emergency services are braced for further heavy rainfall which is expected to coincide with high tide in the early hours of the morning.
A group of residents in the Pohara area of Golden Bay have been evacuated after a log jam blocked a creek in the Pohara Valley and subsequently gave way.
A number homes in Nelson have been evacuated and some people have also self-evacuated.
The Takaka Hill is affected by slips and has been closed. It will not re-open before the morning.
Collingwood Township and beyond is also cut off by slips.
Police are busy responding to calls for service with weather-related jobs and ask the public to hold off making any non-urgent calls that are not related to the current emergency until tomorrow.
Evacuation centres have been set up in Nelson at the Suburban Club on Tahunanui Drive and in Golden Bay at the Onetahua Marae in Pohara.