MetService has a heavy rain warning in place for the West Coast, while downpours have eased in Canterbury and northern Otago.
A deep low will hover off the coast of Fiordland until Sunday evening before dissipating.
About 30mm of light rain is expected in the coastal hills south of Dunedin up to Sunday evening.
And, after two days of heavy rain, a further 100mm is possible in the Westland ranges on Sunday.
MetService says people in the area should stay alert for rising waterways.