MetService says heavy rainfall and strong winds have yet to reach full force in parts of New Zealand it had forecast to hit.
A severe weather warning has been issued for Bay of Plenty in the North Island and Nelson and Southland in the South Island, with heavy rain expected from Monday night.
MetService said about 40 millimetres has fallen in Northland and only a few millimetres in Auckland and Waikato by Monday evening.
Forecaster Dan Corbett said the main band of rain has started to sweep through in those areas and up to 150 millimetres is expected in parts of the Nelson region and Bay of Plenty.
Lines company Vector says it has dealt with outages in parts of Auckland on Monday and has field crews on alert to respond as soon as possible.
The entire North Island and the West Coast of the South Island remain in an official state of drought after months of dry conditions.
However, east coast drought co-ordinator David Scott believes the rain won't do much to help farmers as it is coming too late in the season.
Mr Scott said the rain will encourage grass growth, but stock numbers have already been reduced.
Farmers expect to take a big hit in earnings and it will take up to two years for them to recover from such a severe drought, he said.
The bad weather is expected to ease by late on Wednesday.