MetService is warning that heavy rain and strong winds will affect the upper North Island on Tuesday.

Rain is forecast to become heavy in Northland early Tuesday morning before moving further south into other parts of the North Island.

MetService Meteorologist Stephen Glassey says a low pressure system deepens west of Northland on Tuesday, dragging down moisture-laden air from the subtropics, which increases the potential for heavy rain.

Heavy rain also moves into Auckland and Coromandel Peninsula on Tuesday where a Heavy Rain Watch is in force. Bay of Plenty and Waikato can expect heavy rain in the second half of Tuesday too.

Accompanying the heavy rain will be strong to gale force northeasterlies and MetService has issued a Strong Wind Watch for Northland, Auckland, and Coromandel Peninsula.

Looking ahead to Wednesday, the rain in the north should have eased to showers for most places as the low moves to the east.

The rest of the week sees a cold southerly move north over New Zealand during Thursday and Friday bringing showers to eastern areas, before a ridge of high pressure moves onto the country this weekend.