Heavy downpours are expected to sweep the Bay of Plenty tomorrow.

Metservice has issued a heavy rain watch for the Bay of Plenty region for tomorrow through to the early hours of Saturday morning.

The watch is in place from 7am tomorrow through to 1am Saturday, with periods of heavy rain that may reach warning levels.

A front is set to move over the North Island tomorrow bringing widespread rain with the heaviest falls likely about the Bay of Plenty and Gisborne ranges.

The eastern ranges of the Bay of Plenty are expected to be the hardest hit.