You absolutely can draft a motion to adopt a code of conduct (which can then even be added to your by laws but will require registering for that).
You can just put a motion that all new people wanting to be on the committee or renominate to be on the committee, sign a statement acknowledging committee expectations under the Act. I just did this at an EGM. I said people need to know what expectations of Committee are when they sign up for it. Everyone was fine with it. I just took the main things from the Act about due care and diligence, good faith, that it is voluntary and only means of renumeration under s46, what a committee can and can’t do etc.
You can remind committee members that they need to perform their function. I asked my committee if you don’t want to perform the functions of a committee, why are you on the committee? You can also apply for orders from NCAT to remove committee members.
I don’t think people have to perform all the things, but at least some of the things. A secretary should reply to any reasonable correspondence.
Get your self nominated onto the committee