Earthquake Commission chairman Maarten Wevers has defended building repairs in Christchurch following the 2010 and 2011 quakes in response to a petition for a royal commission of inquiry into defective work.

With aftershocks continuing across the country following Monday morning's 7.5 magnitude earthquake near Kaikoura, Duncan Webb, a partner at Christchurch law firm Lane Neave and the Christchurch Central candidate for the Labour Party, gave a presentation to the finance and expenditure select committee about his petition with 3,054 signatures calling for a royal commission of inquiry into EQC's repairs in Christchurch.

The problems with defective repairs done through EQC were "on par with leaky homes", Webb said. Some 167,000 homes were damaged by the earthquakes which struck Canterbury in 2010 and 2011, and about 70,000 houses were repaired without a building consent as they did not require consent under the Building Act.

Speaking to Webb's presentation, EQC chair Wevers told the committee there were a number of assertions in the petition he "would certainly not concur with" and the hurdle for calling a royal commission was quite high.


"We do not contest for a moment that there have been shortcomings in some repair work, and there is a range of reasons for that," Wevers said.

A survey of 2,174 properties where unconsented underfloor repairs had been done found that 476 repairs met the building code, while 839 required remedial repairs of which 200 have been completed. Another 844 inspection reports are still underway, he said.

EQC is dealing with 12,000 remedial repair requests, with the total bill estimated to about $70 million, or 2.3 per cent of EQC's total bill.

The act allows replacement without the need for a consent provided the replacement is not substantial, and petitioner Webb said some builders had been "pretty enthusiastic" with their interpretation of substantial.

"There was no third party scrutiny of the repairs, and a lot of those were very significant repairs," Webb said. "There's ongoing research being done and an alarming proportion simply didn't comply with the Building Code."

EQC's Wevers said consenting would have created unnecessary delays: "If we had gone through and consented all the matters we followed regulation not to consent, we would have a much longer tail now of homeowners."

Webb said the issue is not confined to repairs which didn't require and gain a building consent, with some cases of consented work also defective. A shortage of qualified people who can properly identify damage done to houses by the quakes and meant some "hopelessly unqualified" people had assessed damage, meaning inadequate repairs have been done.

"The problem is massive and not going away," Webb said. "This will have a long tail, it will take a long time for defects to become apparent."

Wevers said EQC had taken the view that it didn't want to do invasive investigations such as ripping jib off walls, and the need for further work had often become apparent after the initial repair had started.

"In many cases where repairs have been undertaken, the initial scope has been amended, that is exactly what you'd expect us to do," Wevers said.

Wevers denied EQC has a brief to minimise costs, saying the government agency could neither overcompensate nor undercompensate homeowners under the statute which governs it.