All NZSki staff are being given booster shots on Thursday and Friday, in a bid to help prevent the spread of measles in Queenstown.
It comes after five ski instructors at The Remarkables were diagnosed with measles.
NZSki says it's keeping in touch with school groups who may be attending the ski area, to ensure parents, especially of unvaccinated children, are aware.
Chief executive Paul Anderson said health and wellbeing was its top priority.
"The five staff who have tested positive to the measles virus have been isolated and any staff with potential symptoms are not permitted to work until they receive clearance."
The number of measles cases throughout the country topped 1000 on Thursday - 877 of which are in Auckland.
Southern Medical Officer of Health Dr Susan Jack told Newshub an emergency operations centre has been set up in Dunedin.
"We're wanting to be proactive to frontfoot this, to hopefully avoid it spreading further."
- Measles strikes Auckland school ball
- Measles probably entering NZ 'on a daily basis'
- MMR vaccine eligibility widened as measles outbreak spreads
Cases in Queenstown have reached seven, including the five ski field instructors - many of whom were working while infectious at The Remarkables.
Dr Jack said all needed resources were being used.
"We're predominantly focusing on the situation in Queenstown, but obviously we're a large district and people are travelling around the district and in and out of Queenstown," she told Newshub.
People who have been at the Remarkables ski field in the past two weeks are at risk.
"The incubation period of measles is about 10 days, but it can range from seven to 18 days," Dr Jack said.
A Ministry of Health spokesman told Newshub there are now 1051 cases of the infection nationwide.
Immunisation Advisory Centre director Dr Nikki Turner said it was a "very sad" milestone to reach.
"This was entirely predictable and preventable, so it is very disappointing for us."