Twenty-three people onboard an Australian Navy vessel enroute to help with the recovery effort in Tonga have tested positive for Covid-19.

In a statement the Australian Department of Defence said the positive Covid cases, and their close contacts, are being isolated onboard the vessel which has a 40-bed hospital with operating theatres and a critical care ward.

The Department of Defence is adamant the cases will not stop the Adelaide's mission with the vessel expected to arrive off the coast of Tonga in the early hours of Wednesday morning.

It said it is confident it can deliver the much needed supplies onboard to local authorities in Tonga without transmitting the virus.

Tonga is one of the few remaining Covid-19 free countries in the world and the government has made it very clear its priority is keeping things that way.

Air New Zealand to deliver relief supplies

An Air New Zealand flight is scheduled to take supplies to Tonga tomorrow to help with the recovery from the recent volcanic eruption and tsunami.

Chief pilot Captain David Morgan said 18 tonnes of cargo including fresh water, medical supplies, garments, bedding, and urgent machine and automotive parts will be onboard.

The flight is scheduled to take off from Auckland at 8am.

The same plane will then turn around and depart from Tonga at 12.20pm tomorrow, bringing back passengers and cargo to Auckland.

Tongan diaspora in NZ working overtime to ship supplies home

The Aotearoa Tonga Relief Committee plans on packing 13 shipping containers by midnight tonight so that they can be shipped to Tonga tomorrow.

Co-chair Jenny Salesa said more volunteers are needed at the Mt Smart Stadium donation centre as hundreds of drums still have to be packed.

She said people have been so generous and more shipping containers are still needed.

Twenty-five containers are scheduled to be sent to Tonga on Wednesday if they are all packed in time.