Indigenous Heritage

Can anyone point me in the right direction to track my childrens Aboriginal heritage? I am not Indigenous however my childrens biological father is. There is no contact between the kids and their biological father or his family due to safety issues (court ordered also), so asking them directly isn’t an option.
I strongly believe the kids should have every opportunity to know their heritage and have the opportunity to learn about their culture. I just don’t know where to start. We are based in QLD if that makes any difference, I believe their tribe may have originated in NSW somewhere.
Thanks in advance