Former Finance Minister Sir Michael Cullen will chair an independent review into the flooding of Edgecumbe.
The announcement this afternoon comes as one local resident says hundreds of people could join him in a class action lawsuit over a stopbank breach that let a torrent of water into the Bay of Plenty town.
The review would focus on the infrastructure and the circumstances that led to the breach of a flood wall and associated flooding through the town.
Bay of Plenty Regional Council chairman Doug Leeder said that, as the response effort moved into a recovery stage, it was appropriate a review was undertaken alongside the process.
"Sir Michael has accepted the role of chair and will lead a group of experts through this review process."
Regional councillors would work with Sir Michael, with involvement from Whakatane Mayor Tony Bonne, to establish membership of the review committee.
"We will also work together to establish the official scope of the review," Leeder said.
"In general terms, it will be focused on the events leading up to the breach of the flood wall. That includes design, engineering, maintenance and management of the assets that regional council manages on behalf of the community.
"I appreciate that many people in the community are looking for answers - understandably they are asking how this could happen and what could have been done to prevent it. As an eastern Bay resident myself, I understand that sentiment."
The timing for the review would be mapped out further in consultation with the group, but findings are expected in July.
Support for lawsuit: Edgecumbe resident
Meanwhile, Whakatane District Council community board member Graeme Bourk today said more than 100 residents of the devastated Bay of Plenty town had already signalled an interest in joining a class action.
"It's right in the infant stages, where we are just getting things off the road and seeing how many people are behind us - and there's a lot.
"But once it starts getting out, I would say we'll have five to six hundred people.
"There are people who are under-insured and they need some way of getting their money back."
Bourk claims "incompetence" was to blame for the ultimate failure of a flood wall in the Rangitaiki River - and has the Bay of Plenty Regional Council and Matahina Dam operators Trustpower in his sights.
"They promised us in 2004 at a public meeting they would never allow it to happen again, and this is worse," he said.
Bourk believes Trustpower, which oversees a flood management plan, should have begun lowering the levels of Lake Matahina much earlier than Monday.
"They should have been unloading it weeks before."
He also blames the regional council for not making the flood wall strong enough after the last severe flood 13 years ago, saying cracks had been present in the wall for years.
"The wall wouldn't have come down if they'd had engineers look at it and do something about it."
Bourk said the material under the wall had been too soft, allowing water to get underneath the defence.
Both the regional council and Trustpower have already publicly responded to the accusations, noting protocols were correctly followed and flooding defences had already been upgraded before the one-in-500-year event.
Trustpower chief executive Vince Hawksworth earlier told NZME the company had followed its flood management plan, dropping the dam levels to the lowest level allowed by its resource consent before the rain came.
When the rains did come, dumping 20 times Lake Matahina's capacity over three days, Trustpower began a controlled release of water into the Rangitaiki River.
The question of whether more water should have been released earlier was a valid one, but Trustpower did not have the authority to make that call at the time, Hawksworth said.
Regional council spokesman Peter Blackwood also earlier said there had been regular reports into the stop bank's structural integrity and all upgrades had been completed before the flood.
The level of flooding was well above the design standard of the river scheme, where stop banks had been designed for a one-in-100-year event; at their peak, river flows were more than 30 per cent larger than this.