MetService advises that heavy rain is forecast for the North Island over the next few days.

A subtropical low is developing to the north of the country during Monday and will bring heavy rain to northern and eastern parts of the North Island in the coming days, says a MetService spokesperson.

Watches are in force for Heavy Rain in several areas.

"There is uncertainty about the development of this low," says a MetService spokesperson.

"Stay up to date with the forecasts as changes are likely to be made. More areas could be added, and Watches could be upgraded to Warnings."

A heavy rain watch is in place for Northland, which is valid for 12 hours from 12noon today, Monday, May 20 to 12am, Tuesday, May 21.

Periods of heavy rain, and amounts may approach warning criteria. Thunderstorms are possible from Monday evening.

A heavy rain watch is also in place for Tairawhiti/Gisborne. This is valid for 38 hours from 4am, Tuesday, May 21 May to 6pm, Wednesday, May  22. Periods of heavy rain are forecast, and amounts may approach warning criteria.

A heavy rain watch is also in place for Hawke's Bay, which is valid for 60 hours from 6am Monday, May 20  to 6pm Wednesday, May 22.  Periods of heavy rain are forecast, and amounts may approach warning criteria.