A Blue Card is Queensland's 'Working with Children Check'. The Blue Card system exists to help minimise risk of harm to children and young people. Whether you require a Blue Card depends on your 'usual' work.
In QLD, people offering a health, counselling or support service, as a sole trader and independent contractor, will likely not need a Blue Card, unless their usual sole trader activity is working with people under 18 years old. Usual means your habitually or typically occuring. Please call Blue Card QLD for details and enquiries.
A Blue Card also acts as your Police Certificate check. If you are yet to apply for your Police Certificate and believe you need a Blue Card, you can apply for a Blue Card to save money, instead of needing both checks.
Naturally, the more checks and verifications you have, the more appealing your profile will be to individuals and families looking for services and support. You're welcome to contact the Government for specific info.