Heavy rainfall followed by strong winds are forecast for the North Island's east coast until early Tuesday as a subtropical low pressure system moves slowly over the region, MetService has reported.

A deep, slow-moving low system is expected to dump between 100mm and 140mm of rain north of Gisborne from 10am Sunday, the agency says.

Severe southeasterly gales with gusts up to 90 km per hour will be felt around the eastern Bay of Plenty as the forecasted stormy weather hits the North Island east coast.

It will be especially wet on Sunday afternoon when peak rainfall of 10-20mm before dropping away on Monday morning.

The subtropical low system was moving slowing south-east from Raoul Island where 55mm of rainfall has been recorded in the past 24 hours, MetService duty forecaster Gerard Bellam says.

A high-pressure system over much of the rest of the North Island was 'cradling” the low system and preventing it from moving further south, he says.

Heavy showers and gales were reported north of Whangarei around Tutukaka Harbour late Saturday afternoon.

MetService also warns of heavy rain south of Gisborne city between Sunday 10am and Monday 10am.

Strong wind watches are in place for eastern parts of Northland, Great Barrier Island and north of Coromandel Peninsula.