MetService is warning another bout of heavy rain and wind will hit the country following one that has soaked parts of the South Island's West Coast.
MetService severe weather forecaster Chris Noble said the first system was moving across the upper North Island on Monday night but behind that was a very strong northwest wind flow.
Mr Noble said heavy rain would hit Westland and the Canterbury headwaters overnight and could cause surface flooding and slips.
He said there was some good news, with a ridge due to bring settled weather to the country on Friday and Saturday.
"By the time we get to the end of this event tomorrow morning particularly up in the ranges of Westland will have had anywhere between 100 and 200 millimetres of rain, potentially between 200 and 300 right up in the mountains."
MetService's severe weather warning for heavy rain on Monday also covered the Nelson Ranges and Mt Taranaki.
Northerly or northwesterly gusts of up to 120 kilometres an hour are forecast through until Tuesday morning in Wellington, exposed parts of North Canterbury and Marlborough and exposed parts of Wairarapa, especially hilltops such as the Rimutaka Hill Road.