The short answer is no.
In Australia there is no national governing body for child seat installations - and there never has been. It is not illegal for consumers, or businesses to install their own child seat or a member of the public's. And it never should be - education is the key.
Installing a child seat should not be treated in the same way as electrical work in a house - there is no department that certifies specific members of the public, which means there is no governing body to lodge certificates of installation or certified installers with.
However there are training organisations who provide accreditation for technicians, government or corporations who successfully complete their training. This is how the ACRI Network was initially founded back in 2005, with an intention to bring consistency and best practice guidelines into an unregulated industry. ACRI are the only national training organisation that offer national accreditations, with training programs focused on the following industries' best practices;
Automotive
Government/NPO's
Family Service Environments including Indigenous and Family Day Care Centres
Retail and Equipment Hire
Vehicle Hire
Detailing and Laundering
Professional Technicians
Prisons
ACRI have programs that support independent specialist technicians, national government organisations, large international corporations and even other state training organisations.
Can a member of ACRI issue certificates?
Depending on what the certificate represents, it could be an acceptable policy for member's of ACRI to adopt. If a member offers a "Certificate of Installation" for example it must be represented in the following way;
All organisation details must be clearly visible, including ABN/ACN
Wording must never indicate to the consumer that a certificate is required for installation services, or that it is issued by a government body.
The purpose of providing installation is to empower the consumer to learn the safest way for their child to travel. Education is the key.
Logging of all installations is to be done appropriately:
With respect to client's privacy, and relevant Australian laws
Include a corresponding ID (Certificate number) for future recollection
Must be stored appropriately for up to 5 years
Must be provided to ACRI upon request of both ACRI and the consumer