The government secured passage of a suite of new building regulation reforms late on Thursday, giving it a political win on the final sitting day of the year.

Industry groups have reacted angrily to the news, with the Property Council predicting the new laws will "create more problems than they fix".

The centerpiece of the reforms - which the ACT's building lobby described as among the "most draconion in the country" - is new laws to make construction company directors personally liable for financial penalties and orders to fix building defects.

The measures are designed to target directors who deliberately wind up their company to avoid paying debts or rectifying shoddy work.

Access Canberra will also be handed the power to force companies to fix defects via "enforceable undertakings". The regulator will also provide more information to the public when it shuts down a construction site.

On Thursday, opposition planning spokesman Mark Parton called for debate on the laws to be delayed until next year, echoing a request made earlier in the day by Master Builders Association boss Michael Hopkins.

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The building lobby had provided Mr Parton with last-minute legal advice it received on the legislation, which recommended urgent clarification on whether the laws would apply retrospectively.

The Housing Industry Association and ACT Law Society voiced similar concerns in submissions to a brief Assembly inquiry into the bill, which handed down its findings on Tuesday.

The government's response, which argued that the new provisions wouldn't apply retrospectively, was only tabled on Thursday morning - just hours before the legislation was scheduled to be debated in the chamber.

Mr Parton said the short window made a "mockery" of the committee inquiry process.

While he agreed with the bulk of the bill, Mr Parton said some sections were flawed. He argued that was due, in part, to the government's refusal to consult with industry while drafting the legislation.

"We cannot possibly properly debate this bill," he said. "We haven't had the time to properly examine it."

Greens crossbencher Caroline Le Couteur said she "seriously considered" supporting Mr Parton's call for a delay, but decided instead to vote in favour of the government's legislation.

With the Greens' support, Labor had the numbers to pass the bill.

Minister for Building Quality Improvement Gordon Ramsay, who was absent from Thursday's debate, said the new laws would better protect Canberra homeowners from "unethical operators" in the construction industry.

But Property Council ACT executive director Adina Cirson said the rushed, ill-conceived legislation would create more problems than it fixed in the sector.

In a lengthy statement on Friday morning, Ms Cirson said existing building laws were adequate to protect owners and hold directors to account for poor construction work.

"All my members can see from the proposed changes is more time caught up trying to interpret how the legislation will work, more time in dispute resolution and even more taxpayer's funds wasted in expensive and ineffectual litigation," she said.

Ms Cirson warned that the extra regulation would deter construction companies from working in Canberra. She again called on the government to focus its energy on helping to implement a nationally-consistent set of building standards.

Mr Hopkins was disappointed the bill had passed unamended, as he accused the government of "prioritising politics over genuine reform".

"The laws passed yesterday will hurt the majority of builders performing high quality work in the territory by increasing the risk to run a business, increasing their insurance costs, and leaving company directors and senior officers open to poorly drafted laws.

"The ACT government's historic failure to enforce building laws has already left some in the community with a legacy of building defects. It is now leaving a legacy of poorly drafted building laws," he said.