MetService has issued a severe weather outlook advisory for New Zealand for the week ahead.

A weak ridge of high pressure should extend onto most of New Zealand from the Tasman Sea on Monday, while a weak cold front is expected to be moving northwards along eastern parts of southern and central New Zealand.

A high should spread over the South Island on Tuesday, while a cool south or southeast flow will be covering the North Island, says a MetService spokesperson.

On Wednesday, the high should cover most of New Zealand, while a strengthening northwesterly flow will be spreading onto the southern South Island.

A ridge should lie over the North Island on Thursday, while a frontal rain-band is forecase to move onto the southern South Island during the day.

A strong north to northwest flow precedes the front, and there is a low risk of northwesterly winds reaching severe gale about parts of Fiordland and Stewart Island during the first part of the day on Friday.