The Department of Conservation (DOC) is hopeful it has rid an area of Nelson Lakes National Park of a suspected gastro bug outbreak.
Trampers are being urged to stay away from the Travers-Sabine track near Nelson, after as many as 40 people contracted the virus while walking the route.
Teams were yesterday sent in by boat and helicopter to clean 12 huts, which were wiped down, then sprayed with a bleach solution.
DOC manager John Wotherspoon Mr Wotherspoon said he was still not sure what the bug was.
“We can’t be too sure unless we get a sample from someone. We’ve certainly done everything we conceivably can so far to make the place clean, and to get the message through to people about avoiding the huts.”
Mr Wotherspoon said there was no evidence so far of the bug spreading to other national parks.