Homes are being evacuated in Nelson, as heavy rain continues to sweep across the South Island

Slips and surface flooding have been reported across the Tasman district, and people in Westport, Seddonville and Mokihinui have already been asked to evacuate.

Civil Defence is urging residents whose properties have previously flooded to keep a go-bag ready.

Buller Deputy Mayor Sharon Roche says the West Coast is well prepared after several floods in recent months.

She says this is not unusual or new to them.