So far, the Ruapehu District has largely remained free of the virus.
Last week's case was the first discovered in the district during this outbreak, and only the third of the entire pandemic.
The two previous cases from last year were not residents of the district, having travelled from Auckland to visit Mt Ruapehu in March last year.
The district has one of the lowest vaccination rates in the country, with 67 per cent of its residents fully vaccinated, with a further 9.3 per cent having had one dose.
While the majority of the Ruapehu District, including Ohakune and Raetihi, falls under the care of Whanganui DHB, the town of Taumarunui is covered by Waikato DHB.
The Waikato DHB has been battling a wider Delta outbreak across the region since the beginning of October. There were 21 cases reported in the region on Tuesday.
The Ministry of Health and Waikato DHB have been contacted for comment.