Trampers are being urged to stay away from the Travers-Sabine track near Nelson, until a gastro bug that has hit dozens of people is under control.
Cleaning crews will be disinfecting ten Department of Conservation huts near Nelson today in the hope of ridding the area of the suspected bug.
The Department of Conservation has had reports of at least 34 trampers on the 80km track suffering from vomiting and diarrhoea since the weekend.
Nelson Lakes operation manager John Wotherspoon said extra hand sanitiser, soap packs and bleach had been put in the huts to help stop the germs from spreading, but it was not practical to fully close the circuit.
"Well, if people do need to come to the Travers-Sabine, or they're quite insistent on it, then camping is an option - bring a tent and try to keep yourself to yourself, and of course, bury your toilet waste away from the track and away from any waterways."
He said if people stayed away for at least a week, it could limit the outbreak.
Mr Wotherspoon said teams would be sent in by boat and helicopter to clean the huts.
"We'll basically be going to each hut and giving them a bit of a wipe down of any general gunge, and then using a bleach solution, to do our very best to try and kill these bugs, once and for all."