Niue's Director of Health has confirmed a man with pre-existing health conditions has been hospitalised with Covid-19 after arriving on a quarantine-free flight from New Zealand.

Dr Eddie Akau'ola said the patient is one of five cases of Covid-19 that have tested positive in Niue after landing on Monday on the first quarantine free flight from Auckland since March 2020.

"He is a known COMD case or Chronic Obstructive Airway case. We trigger off our health response, because we all have the protocols in place, now Niue is on yellow alert because we have cases here, if it spread out into the community then we will trigger the red alert."

Dr Akau'ola said the other four passengers are isolating in the community with health workers checking on them.

The man is in Niue Foou Hospital in a mild to moderate condition.

Minister of Social Services, Sauni Tongatule, said the passengers on the flight from Auckland tested positive as part of day one mandatory testing for newly arriving passengers.

Tongatule said all 118 passengers who arrived on Monday local time complied with entry requirements mandated under Niue Law.

He said the cases are contained and there is no community transmission.