Twenty-five close contacts of the Auckland quarantine worker who tested positive for Covid-19 on Friday have been contacted and isolated, the Ministry of Health said in a statement today.
So far, six of these contacts have returned negative tests.
The two premises visited by the worker during their infectious period have had deep cleans.
"Less than 20 people received an alert from NZ Covid Tracer notifying them that they had scanned into the business at the same time as the person who has later tested positive for Covid-19."
The ministry said the case reinforces the importance of using the app to keep a record of where people have been.
There are currently 43 active cases of Covid-19 in NZ.
The ministry has added one historical case to the country's total case numbers.
The historical case is a recent returnee who arrived in New Zealand on 5 October from London via Singapore. Upon arrival at their managed isolation facility, they alerted staff to their previous positive test which was confirmed in London on 19 September.
They were tested again and returned a positive result on 5 October, which indicated an old infection consistent with this earlier positive result.
The ministry is awaiting confirmation that the case has been recorded in the United Kingdom totals, and until then are classifying it as a historical case which will be reported in New Zealand's case numbers.