Auckland was besieged by heavy rain at noon on day four of the city-wide COVID-19 lockdown.
Weather Watch earlier warned of "torrential downpours" slowly crossing the city from the north-west, saying they could result in localised flooding.
The forecaster encouraged locals to drive with caution.
- Got any pictures or videos of the weather? Send them through to email@example.com
MetService said the heavy showers could give way to "a bunch of thunderstorms" later on Wednesday, which are "waiting in the wings" for the afternoon and evening.
However the showers appear to be very localised, with central and west Auckland residents reporting a deluge while some on the North Shore failed to get even a drop of rain.
Western parts of the South Island and northern parts of the North Island are forecast to get plenty of rain this week, with those elsewhere enjoying mainly dry conditions.
The torrential weather comes as Tropical Cyclone Niran, situated in the Coral Sea just north-east of Australia, was upgraded to a Category 2 storm.
The cyclone, which has brought strong winds, heavy rain and turbulent seas to Queensland in recent days, will begin to move east on Wednesday and may put New Zealand at risk.
However Weather Watch says the chances of a direct hit are low, with the Chatham Islands likely to get the worst of the weather if it makes landfall at all.