However, Building and Housing Minister Nick Smith yesterday announced the Government had lodged an application seeking a judicial review into the Ipenz decision last May to drop its investigation into Dr Reay.
Dr Smith believed the decision to drop the probe was flawed.
"We want the decision overturned and Ipenz to complete the investigation into the professional conduct of Dr Reay's role in the design of the CTV building," he said.
Tim Elms, whose daughter Teresa died in the collapse, welcomed the Government's move.
"I'm absolutely delighted. I looked at trying to do a judicial review ourselves, but we just couldn't afford it. We have never had any legal help, or outside help, at all -- it's all been seat of the pants stuff. So to have the Government on board is very pleasing," he said.
"Dr Reay has unlimited supplies of legal help, but to be able to match him now is very encouraging."
Mr Elms, on behalf of 53 bereaved family members who lost loved ones in the disaster, laid a complaint over Dr Reay's involvement in the building design to Ipenz two years ago.
Nigel Hampton QC, who has been heavily involved in working with families of CTV victims, including Srecko "Alec" Cvetanov, who lost his wife Tamara in the disaster, said the families would welcome the backing of the Government as they continued to seek accountability.
"It's got the stamp of the establishment approval on it," he said.
"The families have always sought accountability, or at least an inquiry, so they will see this as a move in the right direction.
"At least then the designer can be put under scrutiny by his professional body and they can weight it and come up with their own assessment in relation to responsibilities."
Mr Hampton expected a hearing would be set down for the next 2-3 months.
Dr Reay would likely be given leave by the High Court to have the right to appear and argue his point of view if he wished, Mr Hampton believed.
"He is obviously an interested party."
Ipenz chief executive Susan Freeman-Greene also backed the Ministry of Business, Innovation and Employment (MBIE) move, describing it is "a desirable step" towards clarifying the law around disciplinary action against engineers who are subject to complaints.
"While Ipenz is named in the application by MBIE as a respondent, we regard a judicial review as an opportunity to clarify the law at a time when the Government is considering a single regulatory framework to govern all building-related occupations," she said.
"We recognise that the events associated with the Christchurch earthquakes have highlighted areas that need revisiting in a disciplinary process that has evolved over many years."
Ipenz has updated its rules to "put it beyond doubt" that members cannot avoid responsibility by resigning.
The Government last year announced it is looking to strengthen the regulation of engineers to "ensure they have the right knowledge, skills and competence" to design safe buildings and to hold them more accountable for substandard work.