Widespread heavy rain is being forecast towards the end of the week as a complex area of low pressure moves slowly southeast over the country.

Fronts associated with this system may bring heavy rain to some areas, warns the MetService.

There could also be widespread heavy rain associated with thunderstorms, especially over the North Island.

'On Thursday, a moist unstably northerly flow is likely to bring frequent and possibly heavy showers to many North Island areas,” says a spokesperson for the weather organisation.

'There is a low confidence in warning amounts of rain for Waikato and the Bay of Plenty to Taranaki, the central North Island high country and for the Tararua Range.

'From Friday to Sunday there is a low confidence in warning amounts of rain for Taranaki, Taihape, the west of Taupo, the north of Taihape, Nelson and the northwest of Marlborough as indicated on the chart.

'On Saturday a slow moving front may bring heavy rain to some eastern parts of the South Island. There is then a low confidence in warning amounts of rain for North Otago and for Canterbury. Note that the greatest risk for Canterbury is south of Christchurch.

'On Sunday there is a low confidence in warning amounts of rain for Taupo, the eastern ranges of the Bay of Plenty and for the Tararua Range.”

The seven day forecast for Tauranga. Image: MetService.