The collision happened in Christchurch's Bush Inn Mall carpark.
The floods forced the shingle out of the rivers and onto their land.
The group says it's "saddened to hear such a kaupapa has been disrespected".
The injured person is in hospital with critical injuries.
"We would like to get some money together to assist with organizing another wedding for them as soon as they are physically able to."
The road remains closed and traffic is being diverted where possible
The Christchurch villa was the headquarters for Sheppard's suffragist campaign.
"It will continue happening until there's some sort of laws put into place."
"You guys are foreigners, it's not your country, it's my country and I can do whatever I want," the man allegedly said.