I haven't researched specifically the Australian foreign agent registry. My sense though is that Canada could set one up. How effective it would be....
A lot of these operations are covert or clandestine by nature. Even if you were to put agents and register everyone, my sense is they will find alternate means to evade or circumvent the registry.
There's also no strong evidence one way or another that labelling someone as a foreign agent or an entity might change an audience's mind. For example, YouTube has a labelling procedure. They label anything that comes from, say, a Russian state agency, a Chinese state agency or any state agency. The effects are mixed. People still watch these videos. They still comment on these videos. They still consume these videos. Whether or not that actually deters people from watching or believing it, to be honest, the research is still out.
However, I think Mr. Kwan mentioned something earlier that I think would be worth exploring. That's having a dedicated rapid response hotline for individuals or communities that really need to seek security. This could be helping them with their devices if they're being harassed online, off-line or both. It usually happens at the same time.
We could also explore having an independent agency that's separate from law enforcement, CBSA or CSIS, to address specifically transnational repression. I think that would be really helpful in supporting victims and targeted communities.
I think there are other methods.