The state government says it will rewrite the law governing the way NSW buildings are certified after a damning review found practices for ensuring apartment fire safety were "totally ineffectual" and had caused unsafe buildings to be approved.

The government will announce on Wednesday plans to rewrite the Building Professionals Act in response to a review by former treasury secretary Michael Lambert.

The fatal blaze in a Bankstown apartment block in September 2012. Credit:ABC News 24

The nearly 400-page document, handed to the government last October and released previously in draft, is highly critical of the way in which commercial and apartment buildings in NSW are certified and deemed to be fire safe.

The government says it will pursue more than 70 suggested changes, including more frequent audits and checks against building owners from choosing and paying their own certifiers when such arrangements create a conflict of interest.