Here, we have had four cases of returnees who tested positive after leaving the Pullman Hotel MIQ facility.
Both countries are expected to start vaccinating soon with New Zealand under way as early as next weekend.
Victoria has had more than a dozen confirmed cases linked to hotel quarantine in the past week - workers and guests - and has entered a 'circuit-breaker' five-day lockdown.
Victorian health experts want a day 16 testing regime so far introduced on a voluntary basis in NSW to go Australia-wide.
NSW Health said in a statement: "Day 16 testing was introduced following the identification of people who had developed Covid-19 infection after leaving quarantine in other jurisdictions. Such testing may pick up infection that has developed from exposure during the quarantine period or in those rare instances where cases have long incubation periods".
In the words of Victorian Emergency Services Minister Lisa Neville: "What we've seen... is that this virus is more contagious, it's moving differently, it's lasting longer".
Australia and New Zealand have both long-established Covid-19 quarantine and testing regimes and so are in a good position to notice differences between the original virus and the variants. Britain, which has a top testing system, is only just starting managed isolation.
Neville, who oversees the hotel quarantine system, spoke about a case in January where the virus is thought to have spread between guests as they opened the doors to their rooms to receive deliveries.
"They opened their doors at the same time, for seconds. What it's indicative of is that the strains that are coming from the UK and South Africa are different, and are responding differently."
Victoria is looking again at issues such as air conditioning and protective equipment. Hotel quarantine changes have been brought in. From this week, all quarantine workers in the state are being tested on days off as well as work days. Quarantine meal deliveries are occurring at different times. All workers are wearing face shields and masks.
In Western Australia, quarantine workers are banned from having second jobs. South Australia has begun daily testing of quarantine workers.
On Monday South Africa suspended its planned use of the Oxford/AstraZeneca shot. A small study in South Africa found that the vaccine will not protect people against mild to moderate cases caused by the mutation. The World Health Organisation has stated its support for the vaccine.
The top vaccines have been shown to offer protection against severe symptoms, hospitalisation and death from Covid-19 and work better against the British variant. All the vaccine developers are already working on booster shots for the mutations.
Shabir Madhi, the lead investigator on the South African trial, said the AstraZeneca vaccine would likely protect against severe Covid-19, since it is similar to the Johnson & Johnson vaccine, which does so.
Still, "longer incubation periods" and "lasting longer" are not encouraging considering it will take time for countries to vaccinate their populations as it is.
It feels like that new computer appears to need a software security patch already.
