Health authorities are investigating after a person who visited a Department of Conservation hut in Fiordland National Park returned a weak positive Covid-19 test.
The person returned a second test, which was negative.
Public health staff are now awaiting serology results for the person.
The Green Lake Hut in Fiordland National Park has since been named as a Covid-19 location of interest, and the Ministry of Health has deemed the exposure at the hut as "high risk".
Anyone who stayed in the hut between 7pm Saturday, December 4 and 8am Sunday, December 5 is asked to isolate and get a test straight away and five days from exposure.
"Further isolation and testing requirements will be provided by public health."
The hut is located in a clearing at the southern end of Green Lake and has 12 bunk beds.
"Out of an abundance of caution, the Ministry of Health has published one location of interest," the ministry said in a written statement on Tuesday.
"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."
In a statement, DOC told 1News they were alerted to the potential positive case on Monday, December 6.
DOC said the hut is "not bookable, but available on a first in, first served basis".
"The hut sleeps 12, but because it does not go through a booking system, it is not known how many people accessed the hut during the period of interest.
"DOC will follow MOH guidance on whether the hut needs to be deep cleaned or closed. At this stage it remains open."
The government agency said there is no DOC staff member stationed at the hut, and it is unknown if the person was vaccinated or where they had travelled from prior to the visit.
From December 15, those aged 12 and over must be fully vaccinated to use DOC accommodation.