Those living at the top of the South Island are bracing themselves as more heavy rain sets in

Nelson-Tasman's once again under a state of emergency and have activated their emergency operations centre, with potentially six months worth of rain in 12 days.

There's a high chance the warnings will be upgraded to red, which is as high as they go at MetService.

Mayor Tim King says even the little rain overnight is taking its toll.

He says roads are overflowing where they normally wouldn't after this much rain, which shows how sodden things are.