Amateur Theate ~ Duty of care with children

I am very new to this site, so forgive me if this question has been raised already. I did a search, but was not able to find what I was looking for. Huon Valley Theatre is a small amateur theatre in Tasmania. We frequently stage musical and plays that involve children. I am interested in finding out what legal obligations we have with respect to those children. For example, are adult members of the company required to have police checks? I would be grateful if someone can point me to where I could find information about this