An emotional New Zealand prime minister Jacinda Ardern says a high-risk recovery of bodies on White Island took an enormous amount of courage for military personnel selected to undertake the dangerous mission.

Speaking to reporters on Friday, New Zealand Defence Force Colonel Rian McKinstry revealed members of the NZ military’s explosive ordnance disposal squad were among hundreds of people involved in the astonishing body retrieval operation on the active volcano.

In the end, it came down to six men and two women from the New Zealand defence force’s explosive ordnance disposal team – or E Squadron – setting foot on Whakaari’s other-worldly surface to complete the mission.

“It was unique,” Colonel McKinstry said.

New Zealand Police and the Defence Force, utilising data from geological monitoring agency GNS Science, ticked off on the plan on Thursday.

The latest seismic information was that tremors were down on the previous night, but still drastically up on the lead-up period to Monday’s deadly blast.

“Our assessment in consultation with GNS Science was that there was a 6 per cent chance in any three-hour period that the volcano may erupt,” Colonel McKinstry said.

“That met our threshold, our work and safety requirements. It was safe enough to put people on the island.”

‘They looked like astronauts’

Guarded from the elements wearing “personal protective equipment”, the eight bomb squad members looked like astronauts.

“It’s a yellow hazmat suit with a hood,” Colonel McKinstry said.

“It has a closed-circuit breathing apparatus system, a gas mask, so the operator while they’re on the island can operate within a closed system and be protected from any gases.”

The systems contained enough oxygen for a trip of up to four hours on White Island before returning to the nearby navy vessel, the HMNZS Wellington.

“The equipment that the operators are wearing on the island is significant in terms of its weight and how it restricts movement,” New Zealand police deputy commissioner Mike Clement said.

The identities of the heroic defence personnel have been kept secret, but Colonel McKinstry was happy to talk about their character.

“Because of the bomb disposal nature of the trade, they’re very level-headed,” he said.

“They came from our explosive ordnance disposal squad … an eight-person team consisting of six men and two females.

Ms Ardern revealed she had visited one hospital as consular officials work with families to reunite loved ones.

The daring, high-risk mission recovered six bodies from the island. Later, specialist divers were deployed to search for a seventh body.

A surveillance team will renew efforts to find the eighth and final body, which police believe is on the island.

“We know at least one body is in the water and divers on the Police launch Deodar are currently attempting to recover this body.”

“We are making every effort to locate and recover the two remaining deceased,” NZ police said.

“This has been a harrowing event for the Whakatane community and those family and friends directly impacted by the eruption of Whakaari / White Island.”

Today @NZDefenceForce and Police staff have successfully recovered six bodies from Whakaari / White Island.

Unfortunately, the recovery option is not over as two people remain unaccounted for. https://t.co/C0ouwIweLQ

Photos: NZDF pic.twitter.com/XNEw78jWxH

— New Zealand Police (@nzpolice) December 13, 2019

Earlier, they announced six bodies had been recovered, and taken to HMNZS Wellington.

Five of the bodies are believed to be those of Australians.

Those thought to be on the island are Queenslanders Jessica Richards and her daughter Julie, Coffs Harbour couple Richard Elzer and Karla Mathews, and New Zealanders Tipene Maangi and Hayden Inman.

Adelaide schoolgirl Zoe Hosking and 21-year-old Melbourne woman Krystal Browitt are also presumed dead, although their deaths have not been officially announced.

• Read more: The Australians missing and dead in volcanic island tragedy

“We just want to bring everyone home,” Ms Ardern told ABC radio on Friday morning.

The high-risk mission took place despite raised seismic activity in the wake of Monday’s blast.

GNS Science warned there was a 50 to 60 per cent chance of a further eruption, posing a major threat to the operation and the lives of the team on Whakaari.

An update issued while they were on the island said the “level of volcanic tremor has dropped but remains very high compared to pre-eruption levels”.

‘Absolute bravery’

Alongside the defence and police vessels used in the operation, family representatives and Maori community members also headed out into the Bay of Plenty at first light on Friday.

They conducted a spiritual service close to the island before returning to shore, embracing remaining family members.

The dangerous operation to recover the bodies began with the retrieval team landing on White Island four hours after leaving Whakatane wharf. They gathered bodies from close to the crater, all the while hoping the volatile volcano remained stable.

Their high-risk mission generated anxiety and high emotion in Whakatane.

Before rescuers set off, “a blessing was held at sea with representatives of the families of the victims of the Whakaari / White Island volcanic eruption”, deputy Police Commissioner John Tims said.

Members of the Whakatane community have gathered at the shoreline, waiting for the return of bodies from Whakaari / White Island pic.twitter.com/yYRbEb8TOt

— Mark Schliebs (@mark_schliebs) December 12, 2019

In announcing Friday’s retrieval effort, Deputy Commissioner Clement acknowledged there were “a number of risk factors” but maintained bringing back the bodies was “our focus”.

The mission was monitored and co-ordinated from the mainland by the expert team, including geologists.

A karakia is underway at the Whakatane boat ramp cordon. There are about 50 whanau and friends here, with more arriving every minute. @radionz #Whakaari #WhiteIsland pic.twitter.com/wmnPv6sbKx

— Katie Scotcher (@katiescotcher) December 12, 2019

Meanwhile, eight survivors of Monday’s tragedy are being treated in NSW and Victorian hospitals after being transported from New Zealand’s burns units.

More are expected to arrive in Australia by the weekend.

Coffs Harbour man Jason Griffiths and teenage Sydney brothers Matthew and Berend Hollander are among the eight Australians confirmed dead, having died in hospital.

Matthew, 13, and Berend, 16, have been remembered fondly by their Sydney school Knox Grammar. Their parents, Martin and Barbara, are still unaccounted for.

Year 10 student Berend Hollander and his Year 8 brother Matthew. Photo: Hollander family

Mr Griffiths was travelling with Ms Matthews and Mr Elzer, both 32, on the Ovation of the Seas cruise ship when they took a tour of White Island.

Their six travelling companions – Alex, Daniel, Ellie, Leanne, Paul and Samantha – remained on the ship and said they were “devastated” to learn the trio were visiting the island when the eruption occurred.

Relatives of the Langford family from Sydney have indicated on social media they believe father Anthony, mother Kristine and daughter Winona, 17, have died, while 19-year-old Jesse survived.

Zoe Hosking’s mother Lisa Dallow has been transferred to The Alfred hospital in Melbourne. The 15-year-old’s stepfather Gavin Dallow, 53, was confirmed dead on Wednesday.

Some 47 people, including 24 Australian citizens, were on the island when the volcano erupted.

Eight Australians are confirmed dead, two are presumed to have died and 13 are in hospital fighting for their lives with severe burns.

-with AAP