In Australia and the UK, problems within the fire safety market have resulted in both the Executive and private sector carrying out their own investigations; by the Executive: Shergold Weir Report (Australia), and the Hackitt Report (UK); and, by the private sector: the Warren Centre’s (Australia) fire review program. Because of the findings, some fire safety laws have been changed, by the Executive. New Zealand’s fire safety laws, particularly those below that of the Building Act (i.e., subordinate laws), have also undergone significant change since 2012, again, made by the Executive and have not gone without debate. Some changes, such as compulsory design procedures in a verification method, have caused notable discontent. In response, the New Zealand government funded fire review programs to investigate these issues. This paper looks at how the Judiciary has the power to rule over any law changes made by the Executive under judicial review circumstances in Australia, the UK, and New Zealand (“Westminster countries”), using the compulsory design procedure within a verification method as an example. When analyzing this change against the statutory Acts and Westminster judicial doctrines that the Judiciary must rule within, it is concluded that this design procedure is inconsistent with the New Zealand Building Act and therefore illegal, that there are strong grounds for judicial review, and using judicial review principles to analyze construction laws during the bidding, design, and construction process is recommended when working in Westminster countries.