The Southern region is the fifth district health board in New Zealand to achieve the 90% double Covid vaccination mark.
The Ministry of Health said the board passed the milestone this morning.
The feat may have been reached not a moment too soon, as the Ministry also reported a border case in the region was under investigation.
''This person returned an initial weak positive test and a second test has returned a negative result,'' a Ministry spokeswoman said.
''Public health staff are currently awaiting serology results for the person.''
The Ministry said that ''out of an abundance of caution'' it would publish one location of interest: currently the sole southern location on its website is the Department of Conservation Green Lake Hut in Fiordland National Park, from 7pm Saturday to 8am Sunday.
Officials regard the remote wilderness setting as a high-risk for anyone in the same venue.
"We would like to remind people of the importance of getting a test, especially if you were at or around the location of interest at the time or generally if you have any symptoms, no matter how mild they maybe."
Nationally, 98 new community cases were reported today: Auckland (74), Waikato (10), Bay of Plenty (8); Taranaki (1); Nelson Marlborough (5).
There are 66 people in hospital, including seven in ICU.