Documents show the country's major certifier of building products has been the subject of complaints, warnings and investigations since it began.
Certmark founder John Thorpe joined the powerful Codemark scheme in 2011.
Documents reveal at least five Australian companies lodged complaints to regulators about Certmark between 2011 and 2019.
Some of the complaints were from Queenslander Steve Marskell, who got a CertMark to do a Codemark for his magnesium board in 2011.
