Efforts to contain a covid outbreak on Vanuatu's Pentecost Island are being hampered by a lack of testing equipment.

RNZ Pacific's correspondent in Vanuatu reports chief Visisio Bubunbah as saying the government has under-estimated the omicron situation on the island.

Bubunbah said locals believe the virus is now covering the whole island after it was first detected on Pentecost last Wednesday.

Forty-three cases have now been detected on the island after the discovery that 27 students at Ranwadi School were infected, after authorities originally determined they had had the flu.

But testing around Pentecost had to be suspended at the weekend due to a shortage of testing materials.

The Penama health manager Markson Tabi has confirmed the shortage but says they expect to be able to resume today after the arrival of 1,200 Rapid Antigen Tests, 2,000 sets of personnel protection equipment and 2000 masks.

It is understood these are the first masks to be sent to the island.

Tabi said the supplies will be distributed to the health centres, dispensaries and clinics.

Our correspondent says nothing is known yet about how the virus managed to reach Pentecost, given the lockdowns.

Meanwhile, a Pentecost mother had to deliver her baby at home on the weekend because of the outbreak.

RNZ Pacific's correspondent reports that Melsisi Health Centre was prevented from delivering babies because the Penama health team was using the facility for Covid-19 testing.

They discovered the Covid outbreak on Friday when 77 students at the island's Ranwadi Secondary School tested positive.

The mother successfully delivered her baby at home - only about 300 metres from the Melsisi Health Centre - with help from a traditional midwife but without the aid of the medical centre's nurses.

The Penama Province area secretary, Eslyn Mabon, said with no hospital on Pentecost health teams have had to use medical clinics for Covid testing.

Health officials had not determined how the virus reached Pentecost since a nationwide lockdown preventing travel between the islands of Vanuatu began more than a month ago when Covid-19 was first detected in Port Vila and Luganville.