New Zealand volcano: Hero tour guide skipper who turned his boat around after eruption to save injured tourists

As New Zealand Police announced a criminal investigation into the deaths on White Island and a sixth person died as a result of the volcanic eruption, it emerged that the death toll could have been higher were it not for the efforts of one tour boat captain in helping the rescue mission.

Paul Kingi was a skipper on the White Island Tours boat, working alongside his friend Hayden Marshall-Inman, who did not survive the explosion.

In a post on his company website, Pursuit Fishing Charters owner Rick Pollock, a 40-year veteran of the industry, said he had worked with Mr Kingi for five years and described him as "an outstanding man" and "amazingly resourceful".

Mr Pollock said Mr Kingi had left the White Island "only minutes before the eruption", but immediately turned around, to be "the first back on, rescuing and assisting numerous injured back onto the waiting boats".

"He went back again and again, ignoring the toxic environment and personal risk, until he was satisfied there were no more obvious survivors remaining… I'd like to recognise Paul for what he is on this occasion, nothing less than a hero," he said.

Mr Pollock added that he felt "devastated" for those affected by the disaster.

"Initially as the reports were coming through I never thought it would turn out to be such a dire situation… Now we are forced to accept the severity of this event with many deaths and injuries. No doubt the fallout will continue to unfold as more information becomes known," he said.

Mr Pollock expressed grief at the loss of Mr Marshall-Inman.

"I've known this young man since he was three years old…. He put his all into the task at hand with his superlative people skills and broad smile coming to the fore… Sadly, this effervescent man's life has come to an end being the first deceased to be identified."

"I can't imagine what his family is going through… My heart and thoughts go out to them in this most difficult of times."

At 10.22pm local time Tuesday New Zealand Police confirmed that a sixth person had died as a result of the explosion on White Island, also known by its Maori name of Whakaari.

The deceased had been evacuated and treated at Middlemore Hospital but died of their injuries.

Earlier in the day Deputy Commissioner John Tims announced a criminal investigation into the deaths would be conducted, along with a WorkSafe New Zealand investigation.

Health Department spokesperson Dr Pete Watson said 27 of the 31 rescued people had suffered severe burns.

There are still eight people missing.