A tour operator who helped rescue people from New Zealand's White Island after a volcano eruption that killed at least six people has been hailed as "superhuman".

Key points: Paul Kingi returned to the island to help survivors escape

Paul Kingi returned to the island to help survivors escape He was praised as "nothing less than a hero"

He was praised as "nothing less than a hero" Tribute was also paid to victim Hayden Marshall-Inman

Paul Kingi left White Island by boat "moments before" the volcano erupted, according to long-time friend Rick Pollock, who heard the story from Mr Kingi directly.

In a lengthy Facebook post, Mr Pollock praises his friend as "nothing less than a hero" for going back to the island in dangerous conditions and helping numerous survivors onto his boat.

Rescuers bring a boat load of tourists away from White Island. ( Supplied: Michael Schade )

Photos taken by witnesses show crew members from White Island Tours, including a man believed to be Mr Kingi, bringing injured people to safety.

"He went back again and again, ignoring the toxic environment and personal risk, until he was satisfied there were no more obvious survivors remaining," Mr Pollock said.

Yet this "superhuman effort" was unsurprising to Mr Pollock, who said Mr Kingi had previously taken control in bad situations.

"Indeed, I was shipwrecked with him once for five days on an uninhabited island!"

Mr Kingi was not the only tour operator to respond to the disaster. Three private helicopter pilots took twelve injured people off the island within a few hours of the disaster, despite thick dust, smoke and volatile conditions.

Emergency rescue helicopters also airlifted victims to hospital, with paramedic Russell Clarke saying the ash-covered scene reminded him of Chernobyl.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 52 seconds 52 s Pilot Mark Law says victims were exposed to the same pressure that blew a helicopter off its platform

Tribute to 'effervescent young man'

Tour guide Hayden Marshall-Inman, an experienced New Zealand tour guide, was the first victim named.

He was well-known to Mr Pollock, first as a close friend to Mr Pollock's son, and later as a relief crewman at his fishing charter business.

Tour guide Hayden Marshall-Inman was remembered for his "superlative people skills and broad smile". ( News Video )

A young man with a "kind disposition", Mr Marshall-Inman spent time in the United States working with young people at summer camps, before beginning a career in eco-tourism and obtaining his skipper's licence, according to the Facebook post.

Mr Marshall-Inman was an "effervescent young man" with "basic enthusiasm for life", Mr Pollock said.

"The word devastation comes to mind here — in totality," he said.

"While I'm finding it most difficult to come to terms with all this horrible revelation, I can't imagine what his family is going through."

Other friends of Mr Marshall-Inman have lauded his selfless character, describing previous acts of heroism.

"He's always put everybody else before himself," friend Eruera Stephens said.

"He would have made sure everybody else got off the island before him."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 34 seconds 34 s Eyewitness video shows tourists being evacuated from White Island after the devastating explosion.

Australians remain missing

While the death toll from the disaster stands at six, at least eight people are still missing, all of whom are Australian.

Another 31 people are injured, with at least 27 suffering burns to more than 30 per cent of their bodies.

Rescue teams hoped to land on the island on Tuesday to recover other victims.