Waiho Bridge would still be there if NZTA acted on locals' warnings, Westland mayor Bruce Smith says, and he is calling for hazard management across New Zealand to make better use of local knowledge.
NZTA had replied that all would be "fine". It has promised it will fix the Waiho Bridge within 10 days at a cost of about $1 million.
Mr Smith told Morning Report the bridge could still be there had something been done.
"I don't think there's any doubt about that," he said.
"Logan Skinner and the locals in Franz are very competent people. They walk the river every day."
He said there had been two meetings within the past two weeks after the community raised its concerns about the bridge, and criticised the agency's response.
"I was down there - there was NZTA, there was regional council, there was all the affected parties and at the meeting when the regional council raised the fact that 'look, you need a consent to do this' then NZTA said 'look, any work at all on the northern side of the Waiho we're going to object to'.
"That was their statement, that's because they put tar seal ahead of carpet."
He said Franz Josef infrastructure had problems going back seven to 10 years, which was often because of the Transport Agency objecting to consents.
"The issue ... that he's raised is just one of a number.
"NZTA refusing to or saying that it's going to object to a consent: we've got a gravel wall that was built before Christmas - $130,000 of local cash, they had a pile of rock that costs up to $30 a tonne to put on the wall - the consent allowed them to put the gravel up but they weren't allowed to move the rock 20 metres to put it onto the wall.
"Of course, the gravel's washed away - $130,000 just gone."
He said hazard management all across New Zealand needed more input from locals, who know what the problems are but cannot act on it.
"We need to have more local direct input into the management of hazards right around New Zealand.
"The locals know what's required, but because of the myriad of parties deemed to be affected in a process to get a consent, 'do nothing' is the fallback position."
"We've got to have the people that live on the site ... actually involved, being listened to because if we don't this is the type of thing that potentially could have been avoided."
He said he did not want to single out officials but would continue to press the agency on the matter of the bridge.
"We are bearing the brunt and these discussions are ongoing.
"Clearly there will be further discussions and, you know, I don't want to pick out the individuals because in most of these organisations they follow the directives from further up the chain.
"But we will certainly be saying 'guys, if we had just taken five minutes to read this and say 'there is a problem' and maybe done something about it, maybe that bridge would have still been there'."
The Transport Agency has declined to be interviewed.
But in a statement it said there was no evidence to support suggestions that a lack of maintenance or earlier work upstream were responsible for the failure of the bridge
NZTA system manager Pete Connors said it was unlikely anything could have been done to save the bridge from the force of the swollen river and the rock pounding the bridge's piers.
He said in in recent months the river had built up material in the centre of the channel, pushing its main channel across to the right/ north side bank.
"When combined with the significant flood event, this resulted in extremely high river velocities in the main channel which aggressively attacked the rock groynes that protect the bridge and the rock embankment protection at the northern abutment (where the bridge joins the bank).
"The scour and displacement of rock resulted in the shallow pad foundation at the northern abutment being undermined. The northernmost pier (which stands in the river) appears to have been hit by a large boulder, causing the pier to buckle and fail, causing the collapse of the main northern span. Once that entered the river floodwater, subsequent bridge spans were pulled downstream off their pier foundations."
The Transport Agency aiming to replace the bailey bridge within 7-10 days.