He admitted he was initially ‘‘surprised’’ by the decision to move the whole country into Alert Level 4 after a 58-year-old man in Devonport tested positive for Covid-19.
However, that changed when more details emerged, including that the man had travelled to the Coromandel and had contact with people who may have then travelled to other parts of New Zealand.
Prof Baker said enforcing Level 4 across the country would also help prevent people leaving Auckland to travel to areas with no or fewer restrictions.
‘‘We have seen before how difficult it is to actually close the borders to Auckland.’’
It was important that people in the South Island remained vigilant, he said.
‘‘We don’t want any unpleasant surprises, as they are seeing in New South Wales ... cases are appearing in unexpected places.’’
It only took ‘‘fleeting’’ contact to be infected with the virus, he said.
‘‘When you do not have a clear link to the border, what you are seeing may be the tip of the iceberg and you have to assume the worst.’’
Prof Baker said the ‘‘critical’’ advice for people was, if they had cold or flu symptoms, to contact healthline and get tested.
He hoped the situation would also be a chance for the Government to address two ‘‘gaps’’ in New Zealand’s Covid-19 defence.
Those were, he said, making QR scanning mandatory for high-risk indoor environments and revising the alert level system, so it was more clear when masks were required.
Student Joshua Gilchrist was among the crowd at New World Centre City, in Dunedin, after hearing the news.
‘‘We are just getting the essentials to get us through the next few days; plenty of beer and snacks,’’ he said.
Nancy Higgins, of Blueskin Bay, spent two and a-half hours at New World last night.
‘‘I’m not angry about it. It is something we have to do to keep everyone safe.’’ she said.
In Central Otago, residents descended on Alexandra’s sole supermarket — New World — en masse, causing traffic snarls on Centennial Ave.
Similar queues formed at bottle stores and service stations had bumper-to-bumper traffic.
There was congestion at supermarkets in Cromwell, despite where announcements reassuring customers they would be open today.
The Southern District Health Board said in a statement a move to Alert Level 4 meant the majority of scheduled surgeries and outpatient appointments would be postponed for three days and would be reassessed depending on alert level changes.
No visitors will be allowed in hospitals unless on compassionate grounds, but one parent may stay at the hospital if a child is being assessed, treated, or is admitted.
The Dunedin City Council also issued a statement, saying it continued to prioritise supply of critical services such as water and wastewater, and rubbish collection.
At Level 4, council facilities, including libraries, museums, swimming pools, and sports and recreational facilities, must be closed.
The No 1 service to and from Palmerston, which doesn't normally operate on Saturday, will run a normal weekday service. Passengers are required to wear masks.
Two University of Otago public graduation ceremonies planned for Saturday have been cancelled.
A spokeswoman said today the change to Alert Level 4 meant all degrees would now be conferred and diplomas awarded in absentia.
- Additional reporting by Jared Morgan