The heavy rain that's been hammering the West Coast of the South Island over the past few days is set to continue for much of the day

MetService says it will clear south of Hokitika at night.

Meteorologist Dan Corrigan says over three hundred millimetres has fallen in the southern part of Westland, with some getting nearly four hundred in this rainfall event.

He says even for the West Coast, which regularly gets heavy rain events, this is a severe amount of rain.

Corrigan says there's a chance of thunderstorms in parts of eastern Otago and the Canterbury plains this afternoon and evening.