New Zealand has been affected by tens of thousands of thunderstorms last week and all of them delivered significant heavy downpours inland, some with flash flooding.

In Tauranga, lightning lit up the night sky across the Bay of Plenty on Friday evening.

The thunderstorm struck about 9.30pm with thunder still rolling around the sky after midnight.

"The map below clearly shows you where the bulk of the daytime downpours formed - it's a helpful map as it shows why some coastal fringes in New Zealand are drier than average while inland areas are not," says WeatherWatch,co.nz

"More rain is coming in the days ahead, with at least two low pressure systems crossing New Zealand between Wednesday and Saturday."