EQC has spent $160 million remediating botched and incomplete repairs on quake-damaged Christchurch homes, which is almost $100m more than what was estimated to be the "overall" cost.
Former EQC Minister Gerry Brownlee said in June 2016 that the "overall" cost of remediating repairs was estimated to be between $60m and $70m.
However, information provided to Checkpoint with John Campbell under the Official Information Act reveals the total cost to date is $160m, excluding cash settlements.
The costs have skyrocketed from the $7m EQC had spent on remedial repairs in May, 2016.
EQC Minister Megan Woods said she suspected when she was in opposition that the true extent of remedial work had not been revealed.
"I think one of the things that was really evident to me back there was the previous National government was wilfully ignoring the scale of the problem in front of them," she said.
"And the fact they couldn't see, the fact they needed to scale up and have more staff and do things differently, were really evident back then and I think the numbers we're seeing that have had to be spent on these repairs are testament to that now."
When Mr Brownlee was asked when he found out the costs had risen to $160m he said he did not "recall", and refused to answer any more questions.
However, in 2016 there were callbacks for checks and further work on 16.3 percent of all repairs carried out under the Canterbury Home Repair Programme, information provided to Checkpoint shows.
"We could have actually got people back on with their lives if the previous government had been willing to face the scale of this problem and actually scale up the organisation to deal with it then. Instead, now - this many years down the track - we're having to deal with it now," Dr Woods said.
"One of the things that does frustrate me was that some of these repairs have got worse because they weren't dealt with quickly. Obviously time can make things that are broken a bit more broken."
Dr Woods has asked EQC to tell her how much it had paid in cash settlements for re-repairs, as there had been an "emphasis" since 2016 on getting people to cash settle rather than having someone appointed by EQC go in and repair their homes.
She was also seeking clarity on how many further homes may need re-repairs and how much that could cost. They are questions she had as the incoming minister, and is one of the reasons why she appointed an independent ministerial advisor.
"I think it's a failure of political management and leadership. The minister's responses, the previous minister back in 2016 was to not take this seriously. It was wilfully downplaying it and making light of it in some ways."
Asked if she'd been left a mess, the minister quickly responded "absolutely".
"Absolutely, the previous government has left an absolute mess in regard to EQC in Christchurch and in Canterbury. It is something we're determined to fix. I am not prepared to perpetuate the problems that we've seen in the past. I'm making the changes that are required.
"It's simply not good enough for me that people were left unable to get on with their lives and I'm not going to sit by and let that happen."
Meanwhile, National Party EQC spokesperson Stuart Smith said most of the almost 70,000 repairs were high quality.
Mr Smith said there were 67,000 repairs in Christchurch and he understood there were only 2500 open re-repair claims.
"That's like 3.8 of the repairs, and there's a callback rate in a new build situation of 25 percent," he said.
"So on one level it's not good enough, but on another level if you look at it compared to new builds, these things happen."
However, the figures supplied to Checkpoint showed there was an 11 percent callback rate. Mr Smith said that was still lower than the equivalent for new buildings,
Mr Smith said there would have been a worse outcome if the government had instead made people manage their own repairs.
He said repair contracts were enforceable and anyone who had not had a repair carried out correctly should be reimbursed.