The Australian Toy Association has just announced that they will be waiting until October 31st before making a decision on if next year's Melbourne Toyfair. If the virus is still active enough in Victoria to believe that it would prevent a public event in March, then it will go virtual like the New York Toyfair.
Since that is a four month gap from the decision to the event date, there is no way they could know for sure what the situation would be in March. Even if the virus was reduced completely to zero new cases in Victoria by the end of October, it only takes a couple of weeks of cross-border cases or foreign returns to have a city or state in lockdown or limited crowd numbers in public.

The only way we will have Toyfair next year in Melbourne is if before October 31st we have a vaccine approved for Australia and a full rollout is announced to happen by the end of the year.
It will be a shame though, as I've been travelling to Melbourne for the Toyfair (and meeting up with fans) since 208 and next year will be the first year I won't be.