The former Canterbury Rebuild Minister says he is not surprised the bill to fix botched EQC repairs has hit $270m, but the government could not walk away from its obligations.

Photo: VNP / Phil Smith

Gerry Brownlee says the claim he wilfully ignored the magnitude of the Christchurch rebuild is staggering and disgusting.

It's been revealed that the bill to fix botched EQC repairs from the Canterbury earthquakes has hit $270 million - four times what the previous government estimated the final figure would be just two years ago.

The cost of the re-repairs of quake damaged homes rose from a predicted $60m-$70m to $170m, while cash settlements have reached $100m for 8000 homes.

Megan Woods, the Minister responsible for the Earthquake Commission, has asked Treasury to urgently crunch some figures to give the government an idea of its future liability, with many experts warning thousands more homes may be affected.

Ms Woods said Mr Brownlee - who was in the job for six years - didn't just get the figure wrong, he wilfully ignored the problem.

But Mr Brownlee told Morning Report the National government never walked out on Christchurch.

"I find it staggering that the minister says she is going to get Treasury to crunch some numbers. The only reason you do that if you are trying to limit how much you are paying for these things. We never did that at any point."

He also said the repairs were not necessarily botched and may be needed because of the hundreds of smaller quakes that had hit the region over the past few years.

"It's not surprising that some work that was done in the first place may need to be done again. To say it's botched is wrong."

He said the figure of $60m-$70m he provided in 2016 was just an estimate, and it was not surprising that the bill has blown out as more claims have come to light.

"If you look at the total cost of the EQC repair bill down here and then you look at what percentage that presents on a call-back basis, and then compare that to call-backs on a brand new build, and it's still very low."

Mr Brownlee denied that the new government had been left with a fiscal hole because of the cost blow-out, but the repairs were an unquantified liability that the government always carried.

"You can't walk away from the obligation."