Fifty-five millimetres of rain is predicted to fall today.
The rain is causing havoc around Kaikoura with a number of roads closed by the NZ Transport Agency due to rock fall, mudslides and floods.
South of Kaikoura on State Highway 1 remains closed after high volumes of rain caused mudslides over the past two days to block the highway, pushing rock-filled containers over the edge of the road.
The highway between Picton and Kekerengu is reduced to one lane in several places and 30km/hour speed limit.
The NZTA urged drivers to take extreme care.
It closed the inland road to Kaikoura via Waiau and Mt Lyford on Wednesday night and will reassess its safety on Thursday.
Crews are focused on clearing the route, however the ongoing rain means clean ups are ongoing and extensive, the NZTA said.
City council city services general manager David Adamson said winds might bring down some trees but shouldn't cause too much damage.
"Of more concern is the possibility that we might get some flooding around Little River," he said.
"As much as 100mm of rain could fall there over the next 10 hours and that could cause some problems.
Residents in those parts of Little River with a history of flooding should prepare for the possibility of flooding.
"We're monitoring the situation closely and will be ready to respond if problems do arise," he said.
The city council has set up temporary pumps in the Flockton area on Warrington St as a precaution.
A close eye is also being kept on the Port Hills where the damage caused by February's fire has heightened the risk of slips.
The heavy rain has saturated the soils, making the land susceptible to movement.
