The alert status there has been raised to Level 3.
The Minister of Health, Bruno Leingkone, has announced new public health emergency rules, restricting travel between the islands of Tanna, Erromango and Aneityum.
Anyone travelling domestically into or out of Tanna, Erromango and Aneityum either by sea or by air must comply with the approved travel guidelines.
The ruling doesn't apply to those requiring medical treatment in Port Vila or Luganville, the transporting cargoes or materials or equipment for essential services and people providing essential services.
The island of Tanna is one of the most populated island of Vanuatu.
Its schools and markets are being allowed to continue operating but there has to be strict compliance with hand washing, social distancing and other hygiene practices.
Those with symptoms have been ordered to isolate in a healthcare facility, a community isolation centre or at home.
Vaccination rates on Tanna are very low, as they are in much of Vanuatu.
Meanwhile Pentecost Island has now reported 99 positive cases of Covid-19 after the first case was detected there a week ago.
All are from the western side of the island where testing continues, but there has been no testing on the eastern side of Pentecost because of access difficulties.
There is concern Covid-19 has spread there after students from western side schools were sent home last week before Penama Health detected 27 positive cases at Ranwadi Secondary School last Thursday.
Photo supplied Health Promotion Unit Vanuatu