'Millions of dollars' of flood damage in Nelson-Tasman region revealed

Flooded communities in the Nelson-Tasman region remain cut off tonight as the full extent of the clean-up becomes clearer across the top of the South Island.

Farmland in Tapawera, 75 kilometres southwest of Nelson, was still submerged following the torrential rain across the region, with a boil water notice in place, and a warning to treat all water as contaminated.

The rain has eased for now, and roads are slowly beginning to reopen.

Flattened fences with heavy debris show the power of the water which rushed onto one Tapawera farm.

Its owner, Dion McGaveston, said he has never seen anything like it.

"It was raging through here taking a few fences down. It just got worse and worse."

Helpless to stop it, he captured his precious pasture being consumed by a muddy torrent of water.

Resident Raine Turner said she got a "bang" on her door from neighbours who were "shaking and terrified" and told her "oh my god we're flooded".

The streets were left coated in mud, and from above, officials saw just how extensive the damage was.

They flew over the area where a man lost his life while clearing some of the flooding damage. 1News understands he was Peter Lines, a stalwart of the Wakefield community and the New Zealand hop industry.

Minister for Emergency Management Mark Mitchell said the man was a "prominent and respected person in their community", and that his death will be "reverberating through the community".

Far more water had come down than anyone expected. One farmer told 1News he had warned the council a year ago the stop bank would fail, but remedial work was yet to start.

Nelson Mayor Nick Smith said there had been millions of dollars worth of damage to roads, bridges, fences, farm buildings, hop gardens, orchards, and the Great Taste cycleway.

"The worst areas are Wai-iti, Tapawera, Motueka Valley, Kohatu, Motupiko, Pretty Bridge Valley and Tadmor."

Forty-seven local roads were closed with progress in reopening being made, while the damage to State Highway 6 south of the Kohatu bridge was "extensive" where the Motueka River overran it and would require a "major fix", he said.

"The State of Emergency in Nelson and Tasman will remain in place till at least Thursday when we are expecting another front with about 200mm of rain. The greatest risk is further slipping on sodden hills."

Smith also acknowledged Lines' death, saying "Our love goes out to Peter’s wife, family and the Wakefield community at this very difficult time."

Civil Defence controller Alec Louverdis said they were planning for the "worst case scenario".

"It's not good news with everything so wet and inundated."