New Zealand told to brace for more slips and floods as weather turns again, bringing storms, heavy rain, gales

The wild conditions that wreaked havoc in the South Island last week could be about to return, Weather Watch has warned.

The forecaster says an active rain band is expected to make landfall on Sunday before pushing into the likes of Nelson and Marlborough, where some rainfall totals could exceed 100mm.

It comes just days after a state of emergency was declared in Buller and Marlborough, with hundreds of people evacuated following days of heavy rain and floods.

Dead cattle were found washed up on beaches on the West Coast, while multiple slips caused major traffic delays in Wellington and hundreds of homes were damaged by rising waters.

Unfortunately, there doesn't appear to be much let-up if the weekend forecast is anything to go by.

"This Sunday and Monday another more active rain band is expected - and the northerly airflow will again guide that rain to push right into regions like Nelson and Marlborough with rainfall totals potentially exceeding 100mm in some areas," Weather Watch says.

New Zealand told to brace for more slips and floods as weather turns again, bringing storms, heavy rain, gales

"This may cause further slips and flooding. While it's not to the same degree as the rainfall last week, this event is still enough to prompt an advanced heads up."

Before then, another burst of heavy rain is coming for the upper South Island and western and northern parts of the country, along with gale-force winds from the north.

MetService says there's a risk of thunderstorms and periods of heavy downpours on Wednesday afternoon for Buller and the ranges of Westland, with periods where 50-70mm of rainfall is expected.

Heavy rain watches are also in place for Mt Taranaki, the Bay of Plenty ranges east of Opotiki and northern Gisborne on Wednesday, and there is a possibility of small tornadoes in Northland.

"The wintry southerly weather pattern of a month ago is fast melting as a milder, windier and stormier west to north west pattern kicks in," Weather Watch says.

"Rain is forecast today and tomorrow in the upper South Island and regions like Tasman, Nelson, Marlborough and even the upper West Coast may still have more slips with the soil so saturated. Rainfall totals aren't too intense though."