Significant rainfall is coming for parts of New Zealand, in particular the western and northern sides of the South Island with rainfall accumulation approaching 400mm in some locations over the next three days.

The latest IBM rain maps, exclusive to WeatherWatch, show totals of 300 to 400mm in some parts of the South Island, mostly east of Westport and also inland from Hokitika.

Marlborough, Nelson and Taranaki also have high accumulation with some places getting close to 200mm in just 24 hours.

Rainfall of this amount can lead to slips, flooding and road closures.

Use RuralWeather.co.nz or WeatherWatch.co.nz to tap into the IBM supercomputer to see what your local forecast rainfall totals are in the coming days.

All MetService warnings and watches can now be found live here at WeatherWatch.