You must declare it. If you find drugs after checking your luggage, but you don't declare them, you will be fined and will delay you for a longer time. Moreover, you don't want herbs, but what kind of pills you want. You may not ban them or confiscate them. When I return to Australia, I must also declare. When I passed the customs, they saw that there were drugs in my declaration form and asked me what drugs it was. I said pills pills, and he put a tick next to "drugs" on my declaration form (I guess it means no problem).

After that, it's over after the x-ray, and there is no need to check. Not Sydney, of course. Sydney is stricter, but as long as it is honest, as I said just now, no problem. If you are still worried about being checked, put the medicine and food in an easy-to-get place for them to check, because the luggage has been X-rayed first, and it looks fine and they won't check you.

The most important thing is to declare. For a country like Australia, honesty is the most important thing.

I hope I can help you.