People are being asked to delay non-essential travel on the West Coast of the South Island, with heavy rain expected today.
The region was also inundated with rain last weekend - causing slips, road closures and flooding and stranding 970 visitors in Franz Josef.
There were fears there would be no way out before last Friday - however, the road re-opened ahead of schedule on Tuesday.
MetService said today streams and rivers on the West Coast may rise rapidly again and more slips and surface flooding are possible south of Otira.
It says about 60 to 90 millimetres of rain could accumulate before 5pm, and there's a chance of thunderstorms.
Heavy rain warnings are in force for northern Fiordland, the ranges of southern and central Westland, and the Otago headwaters.
Heavy rain watches are in force for inland parts of Southland and the Canterbury headwaters from Arthurs Pass southwards.
MetService said Northland had also experienced some heavy showers today and the rain would head south.