The NCC and Australian Standards are the same everywhere ,AS3600 STRUCTURAL, Concrete, AS3700 STRUCTURAL Masonry, AS4100 STRUCTURAL Steelwork, etc
Strict Code Compliance is 80% of your build
Hence the need for uniform Australia wide regulations for Structural inspections/Certifications
In WA the engineer who does the design, should do the inspection Certificates, but that is not guaranteed
And until legislation is enacted Tightening up Engineering qualifications & certification, ie New Engineers Act 2018
all home builders should take precautions and arrange their own professional structural engineering inspections
Check that they have all their Structural Documentation, Plans & Specifications signed by an licensed Engineer
Any structural Non Compliant Changes, alternate solutions, work variations must be signed as equivalent or better than what was specified by the the engineer. A royal Commission followed by new Government regulations and changes will take years and are not retrospective nor enforceable on old builds which may have insurance claim issues,etc,etc
Forewarned is Forearmed