A team of elite soldiers landed on the White Island volcano on Friday to recover the bodies of those killed in Monday's eruption, despite the ongoing threat of noxious gases and steaming vents.

Key points: Bomb disposal experts entered the crater to look for victims

Bomb disposal experts entered the crater to look for victims The six bodies that were found have not been identified

The six bodies that were found have not been identified Divers are searching the sea for two missing people

For the past five days, conditions have been deemed too unsafe for anyone to set foot on the island.

Friday's recovery mission, a collaboration between the New Zealand Defence Force, the New Zealand Police, scientists and other agencies, required intensive planning and risk assessment.

New Zealand Police Commissioner Mike Bush and Colonel Rian McKinstry from the New Zealand Defence Force revealed how the recovery was executed.

Soldiers wear protective suits to enter the crater of the active volcano. ( Supplied: New Zealand Defence Force )

What happened in the White Island recovery mission?

A team of six soldiers, plus a commanding officer, landed at the island's jetty about 8:00am.

For protection from noxious gases, each wore a full-body hazmat suit and closed-circuit breathing apparatus. Wearing thick protective gear on a warm day meant the soldiers were facing heat stress, with temperatures in the suits over 30 degrees Celsius, Colonel McKinstry said.

On the jetty, the soldiers ran tests to make sure the levels of gas wouldn't overwhelm their safety systems.

The ground crew that landed on the island was supported by other defence force personnel on boats and in the air. ( Supplied: New Zealand Defence Force )

The team then headed across the barren landscape to a site where the bodies were believed to be, finding six of them.

Working in pairs, the soldiers brought the bodies to a waiting Royal New Zealand Air Force NH90 helicopter, which then flew to the nearby HMNZS Wellington.

Colonel McKinstry said the four-hour mission went according to expected timelines.

Plans had been made to minimise risks to personnel on the ground, including an exit strategy in the event of another eruption. Medical staff were on small boats nearby, and a back-up team was on stand-by.

Soldiers battled extreme heat in their heavy-duty protective clothing. ( Supplied: New Zealand Defence Force )

How dangerous was White Island on Friday?

The New Zealand Defence Force worked closely with scientists to determine when it was safe to attempt the recovery.

On Friday morning, scientists determined that there was a 6 per cent chance of an eruption in any three-hour window throughout the day, which was deemed an acceptable level of risk.

It was likely the team on the ground would have been confronted by mounds of ash, noxious gases and steaming vents.

"We cannot downplay the risk involved in this operation," Colonel McKinstry said.

"I want to acknowledge the effort of all of those who have placed themselves in dangerous places today to achieve some resolution for the families and the community."

Who were the soldiers involved?

Those in the team that went onto the island are known as explosive ordnance disposal experts — what we might colloquially term the bomb squad.

These soldiers are trained to deal with dangerous chemicals and potentially hazardous materials.

A mission into a volcano was "unique, but well within their level of capability", Colonel McKinstry said.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 28 seconds 28 s New Zealand military helicopters ferried the rescue teams to White Island.

Members of the unit tended to be level-headed, he said, having volunteered to work with explosives and being highly specialised.

Given the grim task at hand, Colonel McKinstry said all team members involved in retrieving the bodies would be fully debriefed and given medical support if needed.

"For those members of the New Zealand Defence Force, they serve with a sense of duty and a sense of pride in being able to help our fellow New Zealanders and the citizens of the world," he said.

"We will do this when our specialist skills are needed.

"It should not be forgotten that when [soldiers] join the New Zealand Defence Force, they do so knowing that they could be required to be placed in harm's way when New Zealand requires it."

Aside from the New Zealand Defence Force, support for the mission came from the New Zealand Police, emergency services, and mortuary and forensic services, while guidance was given by local Indigenous groups.

Have all victims been identified?

The bodies found on White Island this morning have been taken to Auckland for identification.

Two people remain unaccounted for, though both are presumed dead. One body was spotted in the water earlier this week, and divers are searching at this location.

It's not known whether the other body is on land or in the water.

Relatives wait on the Whakatane wharf for the rescue mission to be completed. ( Reuters: Jorge Silva )

Commissioner Bush said authorities would make "every effort to locate the two missing people".

After the HMNZS Wellington returned to shore, the six bodies were placed in coffins and families were given an opportunity to "receive and farewell" the victims.

Relatives had waited on the Whakatane wharf throughout the mission, waiting to hear if their loved ones had been found.

The coffins were then loaded onto hearses and driven to the Auckland mortuary for identification.

Commissioner Bush expressed confidence that it would be possible to identify all victims and return them to their families.