A worker based at a lodge on the Milford Track has tested positive for Covid-19.
Guided walking business Ultimate Hikes has confirmed that one of its attendants at its lodge, Glade House, became unwell on Saturday and returned a positive rapid antigen test that night.
On Tuesday, she returned a positive PCR test while isolating in Queenstown.
General manager Noel Saxon said Glade House was closed while staff isolated and were tested.
So far, they had returned negative rapid antigen tests but they would receive PCR tests on Thursday.
He said lodge staff were separated from walkers - it meant roughly 100 guided walkers were considered casual contacts.
But there did not appear to be any crossover with independent walkers, he said.
"Our staff members were generally going out on the evening boat on the way back so there's noone on those boats.
"The staff member concerned spent a day out of the lodge on a day off and looks like they've contracted that when they've been out on that day off and then they've come back in, and that's when they've become unwell."
All guides needed to take a rapid antigen test before returning to the track if they had time away, he said.
Ultimate Guides was able to continue operating before Glade House reopened.
"It's the first lodge on the Milford Track for us. It's just about a kilometre up the track from where you get off the boat at the start of the Milford Track.
"What we're doing in the meantime is we're going to spend a night in Te Anau and then get an early boat, and then those walkers will then bypass Glade and walk straight through to Pompolona, our second lodge."
All Ultimate Hikes staff and walkers have been vaccinated.