A further criminal investigation into the collapse of Christchurch's CTV building during the February 2011 earthquake will be undertaken, police say.
Detective Superintendent Peter Read said police had told the families of those who died in the building collapse of the decision.
One hundred and fifteen people died when the six-storey building collapsed in the quake.
The inquiry decision followed assessment and evaluation of a huge amount of information from a range of sources over the last 18 months, Mr Read said.
"Based on this information, we now believe there is sufficient evidence to warrant further criminal investigation into the collapse of the CTV building in February 2011."
Police had engaged the services of engineering consultants Beca to provide an expert opinion regarding the cause of the CTV building collapse.
Beca was also asked to provide expert opinion on whether there were any serious departures from accepted standards by those involved in the building's design or construction that could amount to gross negligence, Mr Read said.
"While police are still awaiting some aspects of Beca's assessment, the bulk of this work has now been completed.
"Based on the work completed to date, police have reached the view that there is sufficient information to warrant further criminal investigation," he said.
"That said, there is still a significant amount of work to be done before any investigation can be completed, the potential outcome of which is unknown."
A group of investigators had been put together to gather more information and where necessary re-interview some of those who had previously given evidence at the Canterbury Earth Quake Royal Commission, as well as any others who could assist with the investigation, Mr Read said.
"The additional material gathered during this phase of the investigation will assist police in determining whether there is anyone who may be criminally culpable for the CTV building collapse.
"While it is still too early at this stage to put any timeframe around when that decision will be made, we will continue to keep all parties informed as we work through the process."
A police spokesman would not be drawn on whether police would be pursuing charges against any individuals involved in the building's design or construction.
"We've got sufficient evidence there to advance a criminal investigation. There's still a lot of work to do before any decision is made about charges.
"We're not going to go into any individuals at the moment.''
