The chief executive of the association's ACT branch, Michael Hopkins, said the government now "needed to find a way" to compel builders to fix historic defects, suggesting legislative changes might be required.

He said builders and sub-contractors should be accountable for delivering shoddy work, but stressed the government was ultimately responsible for enforcing the standards designed to ensure high-quality developments.

In response, the government has called for an end to the "blame game" over who has been responsible for the territory's building woes.

Mr Hopkins on Wednesday gave evidence at the ACT Assembly's building quality inquiry, which is attempting to uncover the root causes of the problems plaguing Canberra's construction boom.

He acknowledged the government had ramped up enforcement activity in recent months, hired more building inspectors and was finally making progress in the implementation of a suite of regulatory reforms.

Those measures might guard against systemic failures in the future, he said. But they would not rectify historical problems, which he argued had been allowed to fester because of government inaction, as well as poor workmanship.

"We have a poor history of enforcing standards in the territory and this has led to a legacy of poorly-designed and constructed buildings which future building reforms are not going to be able to address," he said.

Mr Hopkins said the association had in the past sounded warnings about problem builders to the government, but said "very few of the suggestions had been acted on".

After the hearing, Mr Hopkins declined to name individual builders or projects, but said the government was well aware of where the problems existed.

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He said lax enforcement was among the reasons owners were making compensation claims to the builders' insurance fund, the Master Builders Fidelity Fund.

The Canberra Times last month reported the fund was paying out more than $1 million a year in compensation to owners, despite claims the scheme's narrow eligibility criteria made it almost impossible to secure a payout.

Acknowledging there was "no easy answer", Mr Hopkins said the government had to find a mechanism to compel builders to fix defects which had arisen on their watch.

That might mean the government had to introduce new laws to compel builders to fix defects even after the statutory warranted period had lapsed.

Mr Hopkins' comments are likely to anger those who believe the association, which is the peak industry group for builders and construction professionals, does not do enough to address problems in the sector.

The committee, in particular Labor backbencher Suzanne Orr, pressed Mr Hopkins on how the association accepted members and policed misconduct.

Mr Hopkins said applicants were subject to an "extensive" vetting process, stressing that it "only wanted to accept quality members". Only about 500 of the ACT's approximately 4500 licenced builders are members, he said.

He said the association regularly evicted members for breaching its code of conduct, pointing out that a handful of members were currently under investigation.

The Canberra Times sought responses from Minister for Building Quality Improvement Gordan Ramsay to Mr Hopkins' criticisms of the government's historical approach to regulation, as well as his proposal to compel builders to fix long-standing defects.

In response, a government spokesman said "the blame game occurring throughout the supply chain in the building and construction sector must come to an end".

"The government has already put industry on notice by implementing a thorough policy agenda as well as providing additional investment in compliance and audit activities," the spokesman said.

"Both the community and the government expect industry and their representatives to adopt and respect these approaches by building quality homes for the people of Canberra."