CERA issued a dangerous building notice in April, but demolition was halted while efforts to save the building were explored. A last-ditch offer from an Australian to purchase the building was withdrawn last week.
Cr Livingstone said he learned only on Wednesday afternoon that a demolition contract had been signed and work was set to start at 9am the following day.
He said he was told it would take "something in the vicinity of $7 million more" than earlier estimates above $30 million to restore the building and any further delay to demolition would cost the corporate body some $10,000 a day.
"I do sense the corporate body have explored all avenues. I think they've done their very best to try to save it."
Cr Helen Broughton, who lodged a notice of motion at 4.30pm on Wednesday urgently requesting CERA to grant a month's moratorium, said the earliest a council emergency meeting could be held would have been next Tuesday.
She said her notice of motion was "only a possible backstop" as an emergency meeting would have required signatures from at least five councillors.
"I think it would have been very hard to get those signatures," she said. "The council are very divided on heritage issues and if people aren't aware of all the issues, they wouldn't sign."
Cr Broughton said she was unaware of the imminent demolition until she heard from CERA yesterday morning.
She questioned whether "stronger legislation" was needed to ensure heritage buildings could be saved if they were "deemed to be dangerous".
"How does a city or central government save a building if it is owned by a corporate body of owner who, at the end of the day, doesn't want to save it?"
Cranmer Court body corporate chairman David Chambers said the demolition was "all bad news" and came down to "cost and time".
"We've had to accept we cannot continue to pour good money after bad or there would be nothing left to allow people to rebuild."
Mr Chambers said Cranmer Court represented "31 individual families" many of whom were retired and had "no additional nest eggs".
"We can't fix (the building) for the rest of Christchurch," he said. "We just can't afford to."
An emotional Canterbury Arts and Heritage Trust chairwoman Lorraine North deplored the demolition.
"I see this as an act of deliberate aggression and hostility against the people of this community.
"This is a significant historical site. It is very important to our heritage and it is being deliberately and unnecessarily destroyed."
Ms North said CERA was "inflexible and unreasonable".
"This building could have been left for a long time. It is no threat to the public and demolishing it does not aid our recovery in any way whatsoever."