MetService has issued a severe weather outlook for New Zealand.

A low of sub-tropical origin will move southwards to the west of New Zealand on Monday and Tuesday says a MetService spokesperson.

"An associated warm moist north to northeast flow with embedded rain-bands will affect much of New Zealand through the forecast period.

"The heaviest and most significant rain may be over the northern half of the North Island and northern South Island at the end of the week from Thursday, and into Friday and/or the weekend."

People within these areas should keep up to date with any Severe Weather Watches and Warning issued by MetService over the next week.

For Bay of Plenty, periods of heavy rain are likely through much of the period, but the rain should ease for a time mid week.

"There is high confidence of rainfall reaching warning criteria on Monday and early Tuesday, then moderate confidence of further heavy rain on Wednesday and Thursday," says a MetService spokesperson.

"Over remaining parts of the northern and central North Island, there is high confidence of northeasterly rain reaching warning criteria in Coromandel Peninsula on Monday morning, low confidence of northerly rain about Mt Taranaki reaching warning criteria on Tuesday and Wednesday, then low confidence of northerly rain reaching warning criteria over the northern half of the North Island from Taranaki and Taupo northwards on Thursday."

MetService says In the South Island, there is moderate confidence of northerly rainfall reaching warning criteria about Tasman/Nelson, Westland and Fiordland from Tuesday to Thursday, and low confidence for northern/western Marlborough and Buller during the same period.

"Additionally, there is low confidence of northeasterly winds reaching severe gale about exposed parts of Auckland including Great Barrier Island and the Hauraki Gulf, Coromandel Peninsula and near the Kaimai/Mamaku ranges including eastern Waikato on Monday morning."