Police today admitted the February 22 earthquake disaster in Christchurch "overwhelmed" their communication system.
Inspector John Price, who stepped in to take charge of the police communication centre in the chaotic aftermath of the quake hitting, made the frank admission at a coroner's inquest into the deaths of CTV Building victims this morning.
"The demand for services clearly exceeded the normal response capability of police, however we adapted and met the demand, despite the significant pressures the police, as emergency services, faced," he said.
A review of the communications system is underway.
Inspector Price said there were standard operating procedures for gathering information after a natural disaster, but it was not designed to cope with an event on the scale of the quake that hit at 12.51pm on February 22, 2011.
"We needed to think on our feet and come up with a model that worked based on the circumstances," he said.
The scale of the disaster meant it was difficult to ascertain what was happening across the city, and how to best deploy available resources. The "huge volume" of calls also caused problems for the police radio networks, Inspector Price said.
Giving evidence, the operations commander talked the inquest through graphs which highlighted the volume of calls that police were receiving from the panicked population.
On an average day, police would receive around 250 calls a day - but on February 22 received 3022.
The volume of calls was "overwhelming", he accepted while under questioning from counsel assisting police, Christopher Lange.
And while police were trying to deal with hundreds of missing persons reports, and prioritising resources, they were still getting callouts to other crime, including burglaries.
A large part of his job was trying to keep communication centre staff at Christchurch Central Police Station calm and focused.
He said the CTV site was quickly given priority status after officers on the ground relayed the extent of the disaster.
Inspector Price praised the brave and quick-thinking officers who, acting alone, were at the CTV site within minutes and scrambled into action, trying to find survivors in the debris.
They were not trained to deal with the "very dangerous" site, he said, but added: "They simply did what was required with what was available to them at the time."
Inspector Price accepted that Kaiapoi sergeant Mike Brooklands, who was officer in charge of police operations at the CTV site for more than 12 hours, should have been relieved by a more senior officer.
The coroner's inquiry into the death of eight CTV Building collapse victims resumed this morning to examine what happened in the first 12-24 hours after the magnitude-6.3 jolt struck.
The inquest last year looked at the circumstances of all 115 CTV victims but today started to focus on the foreign nationals who survived the initial pancaking of the six-storey office block.
Tamara Cvetanova of Serbia, Jessie Redouble, Emmabelle Anoba, Ezra Medalle, Reah Sumalpong and Mary Amantillo from the Philippines, Cheng Mai of China, and Japan's Rika Hyuga were all alive in the twisted rubble and steel for a period but unable to be rescued.
They were all students at King's Education School for English Language on the third floor of the building.
Several family members packed into a small makeshift courtroom in central Christchurch this morning to witness the evidence.
In his opening address, counsel assisting the coroner Richard Raymond said it was important for people to recognise that it was "not about finger pointing or apportioning blame".
A crucial part of the hearing will be the detailed analysis of cellphone records of all those who phoned loved ones from the rubble.
The death toll from the CTV Building was more than half of the 185 killed in the quake.
The inquest, set down for three weeks before Coroner Gordon Matenga, continues.