Former and current Greater Christchurch Regeneration Ministers Gerry Brownlee and Nicky Wagner with former Prime Minister John Key.

A new Government report says authorities made mistakes and missed opportunities that led to inefficiencies and bad public perception of the post-earthquake Canterbury recovery.

The Whole of Government Report: Lessons from the Canterbury earthquake sequence was released on Sunday, outlining a timeline of Government actions taken during and following the 2010 and 2011 Canterbury earthquakes.

The report says the Government knew before the September 2010 earthquake that the existing legislation would not be adequate to deal with recovering from a large-scale disaster.

SUPPLIED A diagram referred to by Cera staff as the "horrendogram" - created by the Office of the Auditor General.

Within days of the earthquake, the Government appointed Gerry Brownlee as Canterbury Earthquake Recovery Minister and set up the Canterbury Earthquake Recovery Commission to lead the recovery.

READ MORE:

* Former rebuild minister Gerry Brownlee questioned need to audit Cera before damning report

* Cera staff committed 'serious and sustained' breaches, investigation finds

* Tensions between Cera and Christchurch City Council delayed rebuild, report says

"There were concerns that the organisation of the recovery was struggling to make progress, and that local Canterbury civil defence emergency management structures remained as dysfunctional as they had been prior to the September 4, 2010 earthquake.

"The creation of the Canterbury Earthquake Recovery Commission led to confusion about who was responsible for leading the recovery, and the commission itself was seen as ineffective.

"During this period, the Christchurch City Council was not seen as taking an effective leadership role in the recovery, and it had not produced a recovery plan by the time of the February 22, 2011 earthquake."

After the February earthquake, the Government created the Canterbury Earthquake Recovery Authority (Cera).

The Government considered alternatives, including a Crown agent structurally similar to ACC, a business unit in an existing department, or replacing locally-elected authorities with government-appointed commissioners.

The report said Cera suffered from a bad image.

"As the Canterbury Earthquake Recovery Authority's role evolved over time, uncertainty and confusion amongst the recovery community grew.

"As it took on more delivery roles and released overarching strategic plans . . . recovery partners and the public began to see the Canterbury Earthquake Recovery Authority as 'owning' the recovery and being responsible for solving all problems.

"The kinds of tensions that arose could have been expected, and mechanisms put in place to manage them."

The report said some of these tensions arose because the Government took responsibilities from local authorities that did not have the enough powers to effectively create the Christchurch Central Recovery Plan.

The city council used the widely-commended "Share an Idea" public consultation campaign to create a draft central city plan, but the Government believed it was not specific enough on details and established a new unit within Cera to finalise and implement the plan.

The report said the council "did not have the resources and the statutory powers necessary to lead the recovery of the central city".

"This was perceived by some as central government 'taking over' a local government-led initiative and led to feelings of disillusionment.

"The Canterbury Earthquake Recovery Authority acknowledged that there was a communications vacuum after the release of the Christchurch central recovery plan, which likely contributed to this public perception."

The report said the complexity of the "recovery community" and the evolution of Cera's role over time caused confusion about who was responsible for what.

Cera staff referred to a complex map of relationships between the organisations involved in the recovery as the "horrendogram".

The report said Cera could have reduced its workload and wound down aspects of its activities earlier.

The organisation missed opportunities to pass responsibilities to local organisations, partly because of the "public perception that it was responsible for everything recovery-related".

​"[Cera] was always intended to be temporary, but its culture of fixing problems meant that it missed opportunities to empower other, more permanent, entities to take responsibility and build capability."

Cera had six staff when it began and was expected to grow to 50. By 2014, it had over 300 staff and 150 contractors involved in 24 major programmes and more than 130 projects.

The report said the organisation improved its systems throughout its life, but more improvements were needed until it shut down in April 2016.

Greater Christchurch Regeneration Minister Nicky Wagner said the report helped the Government learn, so response to future disasters would be faster and more effective.

"AThe last six years have been a steep learning curve. We didn't always get it right, but we made the best decisions possible with the information we had at the time," she said.

"One of the key lessons from both international experience and our own recovery planning, is that a single lead entity removes local confusion and provides much-needed certainty.

"[Cera] was up and running quickly, and provided leadership and coordination during an incredibly difficult time."