"Our extremely high vaccination rate is another factor in our favour, as it slows the spread of transmission and reduces the health impacts in those who do contract this virus."
Niue, which has a population of just under 2000, vaccinated 97 per cent of its eligible population in 2021.
Tagelagi said officials who are considered close contacts are currently isolating and being tested.
The country will remain in alert level blue, which is about preparation and readiness to pre-emptively stop the possible entry of the virus into Niue.
All other passengers will be monitored and tested again on day 3.
Currently, quarantine-free travel is only available one way, from Niue to New Zealand.
Tagelagi is asking Niueans to remain vigilant and is encouraging people to wear masks and continue good general hygiene habits.
"We have expected this virus, we have prepared for it, and we are ready to contain its spread. We have remained vigilant; we have caught this case – and now I ask you to remain vigilant too."
According to the World Health Organisation, there are just eight other countries that have not reported any Covid-19 cases – most of them in the Pacific.
The others are Tuvalu, Tokelau, Saint Helena, Pitcairn Islands, Nauru, Federated States of Micronesia, Turkmenistan and North Korea. However, officials have doubted Turkmenistan and North Korea.