A sub-tropical low is forecast to bring severe weather to parts of northern and central New Zealand from Wednesday, MetService said.

A front over the centre of the country should weaken during Tuesday as a high forms over the South Island.

An easterly flow over the northern North Island is set to strengthen during the day with some snow possible about the higher roads of the South Island during Tuesday morning.

Wednesday April 16

On Wednesday the high over the South Island should move slowly eastwards.

"A sub-tropical low is expected to move slowly southwards over the north Tasman Sea bringing strong, moist easterlies to the northern North Island," a MetService spokesperson said.

"There is high confidence that warnings will be needed in Northland for heavy rain and severe gale easterlies."

For Auckland, the Coromandel Peninsula and western Bay of Plenty there is moderate confidence that a rain warning will be needed.

There is low confidence that warning amounts of rain will fall about Gisborne/Tairawhiti and the Hawke's Bay ranges.

There is moderate confidence that a wind warning will be needed in Auckland, Coromandel Peninsula and eastern Waikato and low confidence the warning will also cover the rest of Waikato.

Thursday April 17

On Thursday, a large low should remain over the north Tasman Sea and it directs a strong, moist north to northeast flow over New Zealand.

"There is high confidence warning amounts of rain and severe gale northeasterlies will be experienced in Northland, Auckland, the Coromandel Peninsula, and Bay of Plenty from Rotorua westwards.

"For the rest of Bay of Plenty and northern Gisborne/Tairawhiti there is moderate confidence that warnings will be needed for heavy rain and severe gale northeasterlies."

MetService said there is moderate confidence that a wind warning will be needed about the Waikato region and there is low confidence that warning amounts of rain will fall there.

"About Taupo, southern Gisborne/Tairawhiti and the Hawke's Bay ranges there is low confidence that easterlies will be strong enough to justify a warning and low confidence that a heavy rain warning will be needed.

"There is also low confidence that easterlies will need a wind warning in Waitomo, Taumarunui and Taihape.

"For Tasman west of Motueka, there is low confidence that a heavy rainfall warning and a warning for severe gale easterlies will be in place. There is low confidence that easterlies about Buller and Grey Districts will require a warning."

Friday April 18

The large, slow-moving low over the Tasman Sea and its associated northeast flow over the country may weaken slightly, MetService said.

"There is moderate confidence that heavy rainfall warnings will continue in Northland and Auckland, excluding Great Barrier Island and low confidence that there will be a warning for severe gale northeasterlies in these areas.

"For Great Barrier Island, the Coromandel Peninsula, Bay of Plenty and northern Gisborne/Tairawhiti there is high confidence there will be a heavy rain warning and low confidence that northeast winds will reach severe gale strength.

"There is also low confidence of heavy rain warnings and strong wind warnings being in force for Waikato, Waitomo, Taumarunui, Taupo, Taihape, southern Gisborne/Tairawhiti and the ranges of Hawke's Bay and Tararua District."

MetService said about western Tasman District there is moderate confidence that warning amounts of rain will fall and low confidence that northeasterlies will need a warning.

"For the rest of the Tasman District, Nelson, much of Marlborough and coast of Canterbury north of Ashburton there is low confidence that a rainfall warning will be needed."