On Tuesday, July 23, a strong southwest flow is expected to lie over the country, with showers in some places.

"However, there is minimal risk of severe weather," says a MetService spokesperson.

"A large high over the Tasman Sea should begin moving onto mainland New Zealand on Wednesday, easing the southwest flow there.

"There is low confidence that southwest winds over the Chatham Islands may increase and reach warning strength. Otherwise, there is minimal risk of severe weather over the rest of the country."

On Thursday, July 25, the ridge of high pressure will continue to lie over the North Island and northern South Island.

"A strengthening northwest flow is expected to develop about the south of the country and rain may develop in Fiordland. However, at this stage, it is considered unlikely that warnings will be needed."

On Friday, rain is likely about Fiordland and southern Westland as a front approaches.

"There is moderate confidence that a heavy rainfall warning will be needed in Fiordland."