© Brett Grant
Waiho bridge washed away in the river.
A state of emergency was declared in Westland at 5.45pm following severe weather which has attacked the region since Sunday.
Torrential rain and strong winds have battered the South Island region, forcing emergency services to close roads and evacuate members of the public.
Half a metre to 700 millimetres has fallen in some of the regions catchments.
Earlier this evening, the Waiho Bridge was taken out by rising and rough floodwaters of the Waiho River near Franz Josef.
The river was running at a level of 7.6m, but has dropped back 0.7m from its peak.
NZTA Network Manager for the West Coast, Colin Hey says until water levels drop it'll be hard to tell exactly what damage was done.
"Bailey bridges are usually fairly quick to put back up, so we're confident that we can get it back within a week or two anyway."
Hey says motorist should stay off the roads.
"Travel only if's essential. You won't be able to get along the highway at all, certainly not tonight."
Elsewhere, the Haast River neared a high-level mark but levelled off at 7.6m, which matches its record high. However, the Hokitika River continues to rise, sitting at 5m currently.
Westland Mayor Bruce Smith told Newstalk ZB heavy rain was at the base of their problems but people remain the focus of the council and Civil Defence.
"This is a 100-year event, there is a huge amount of rain. I haven't seen all of the rivers impacted in Westland at exactly the same time," he said.
Comment: Record rainfall has hammered New Zealand's West Coast, with a woman's body found after she was swept away by the floodwaters and a bridge left in ruins.
In the last 48 hours, Cropp Waterfall has recorded 1086mm of rain - the highest level for that time period on record, says Niwa Weather.