A heavy rain watch has been issued for the northern and western parts of New Zealand.

An active trough is expected to move over the country bringing heavy rain to northern and western regions.

Heavy rain Watches and Warnings are in place.

A Heavy Rain Warning is in place for Bay of Plenty east of Kawerau, and Gisborne/Tairawhiti north of Ruatoria. This is valid for 15 hours from 9am Sunday June 23 to 12am Monday June 24.

"Expect 80 to 120 mm of rain, with peak rates of 15 to 25 mm/h, especially in thunderstorms and possible downpours," says a MetService spokesperson.

A Heavy Rain Warning is also in place for Mount Taranaki/Taranaki Mounga, valid for 15 hours from 9pm Saturday June 22 to 12pm Sunday June 23.

"Expect 80 to 120 mm of rain. Peak rates of 20 to 30 mm/h during Sunday morning, especially in thunderstorms and possible downpours."

A Heavy Rain Warning is also in place for Tasman about and northwest of Motueka, valid for  18 hours from 6pm Saturday, June 22 to 12pm Sunday, June 23.

"Expect 100 to 140 mm of rain, mainly about the ranges. Peak rates of 15 to 25 mm/h, especially in thunderstorms tomorrow morning."

A Heavy Rain Watch is in place for Northland north of Whangarei for 12 hours from 12am Sunday, June 23, to 2pm Sunday, June 23.

A Heavy Rain Watch is also in place for Waikato including Coromandel Peninsula, Waitomo, and Bay of Plenty about and west of Kawerau. This is valid for 15 hours from 3am Sunday June 23 to 6pm Sunday June 23.

"Expect periods of heavy rain, with possible thunderstorms and downpours. Rainfall amounts may approach warning criteria or possibly exceed them in isolated areas. Note, heavy rain is expected to ease from the west early Sunday afternoon."

A Heavy Rain Watch is also in place for North Taranaki excluding the Mount Taranaki for 15 hours from 9pm Saturday June 22 to 12 pm Sunday June 23.

Streams and rivers may rise rapidly. Surface flooding, slips, and difficult driving conditions possible.

"Clear your drains and gutters to prepare for heavy rain. Avoid low-lying areas and drive cautiously," says a MetService spokesperson.