Heavy rain and strong winds are being forecast for the Bay of Plenty as the MetService issues a severe weather watch for the region.

A large low pressure system over the Tasman Sea moves slowly across northern New Zealand during the next few days, spreading a band of rain and southeast gales over the North Island and upper South Island.

Heavy rain and strong winds are forecast for tomorrow. Image: MetService.

'Rain is likely to be briefly heavy about the upper North Island today and early Friday, with more persistent falls for Gisborne and Hawke's Bay during Friday and Saturday morning,” says the weather organization.

The watch currently in place is for the possibility that from Friday morning through to Saturday morning, southeast gales may become severe with damaging gust.

'People are advised to keep up to date with the latest forecasts, in case this watch is upgraded to a warning or further areas are added,” says the MetService.

The watch will be reviewed by 9pm Thursday.

Rain over Northland spreading south. See https://t.co/hnwmGxU1gR for when it will likely reach your place.^PL pic.twitter.com/KrSLlbKeZZ

— MetService (@MetService) July 6, 2016