Hundreds of people in Nelson spent the night out of their homes and a state of emergency has been declared after the Matai River burst its banks.

Occupants of 233 homes near the Maitai River were evacuated and cordons put in place at Tasman and Nile Streets.

Soldiers have been patrolling the streets to keep an eye on evacuated properties and all residents are being asked to stay home if possible.

People in 160 homes in low-lying parts of Westport are being asked to leave so they will not have to be rescued if their homes were flooded.

The West Coast is under a red weather warning, but civil defence says Westland rivers have kept within their banks.

Peak flow in the Hokitika River expected this morning but the river is predicted to stay within its banks, they say.

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