Victorian health authorities have confirmed five new community Covid-19 cases - including one mystery case.
This takes the number of this latest outbreak to 40.
One of the new cases is a heathcare provider in an aged care home - authorities say this case is of "extreme concern" because they have not yet been able to trace the source.
Meanwhile, New Zealand's Ministry of Health confirmed 4626 people flew from Melbourne airport to New Zealand between 20 May and 25 May.
It has not yet been able to contact 89 of those travellers to ensure they are isolating and being tested.
Melbourne epidemiologist Professor Tony Blakely spoke to Corin Dann.
