MetService is forecasting more intense bursts of heavy rain for many western parts of the country over the next few days.
It says thunderstorms will continue for areas including Nelson, Taranaki and Bay of Plenty which have already suffered flood damage at the weekend.
Forecaster John Law said on Monday those areas need to keep a close eye on warnings, but the heavy rain would subside towards the middle of the week.
He said while western parts bore the brunt of the storms, the showers should move onto drought-affected areas in the east.
There is a chance some of the storms will cause small tornadoes, he said.