The Bluff cluster last year may have led to the finding of a weak positive Covid-19 test result at Stewart Island yesterday.
The case was revealed by the Ministry of Health yesterday and whether it was a historical case or a false positive test result is being investigated.
As a precaution, the Rakiura Rugrats early childhood centre has been closed for the rest of the week.
Director-general of health Dr Ashley Bloomfield said yesterday the case was a child and it was likely the result was a false positive.
The result came as a family had Covid tests before planning to head overseas. The rest of the family tested negative.
Bloomfield said during the lockdown period last year there were quite a few Covid cases that health teams never knew about.
He said it might have been linked to the Bluff wedding cluster, which was the country's biggest Covid-19 cluster with more than 85 cases.
Stewart Island/Rakiura Community Board chairman Jon Spraggon said he was informed yesterday morning of the existence of the weak positive case.
Southland Mayor Gary Tong said he was contacted at 8am yesterday about the positive result. Everything continued operating as normal while the Ministry of Health followed protocols, he said.
Real Journeys general manager Paul Norris said as soon as staff heard there was a potential case on the island, its Covid response team acted.
The company, which operates the Stewart Island-Bluff ferry, had a few cancellations and it was happy to rebook or refund anyone who had concerns about travelling to the island, he said.
Stewart Island Flights director Bill Moffat said flights to the island had operated as normal.