The brother of Whakaari/White Island tour guide Hayden Marshall-Inman, who died in the December eruption, believes no criminal charges should have been laid over the tragedy.
Hayden Marshall-Inman, 40, died when Whakaari erupted on December 9 last year.
Marshall-Inman was one of two guides from White Island Tours among the 22 who died and his body has never been recovered.
He spent his final moments doing all he could to get badly injured tourist to safety, performing first aid and ensuring they were wearing masks.
On Monday, WorkSafe New Zealand confirmed it had laid criminal charges against 10 organisations and three individuals over the eruption.
WorkSafe chief executive Phil Parkes would not name the 13 parties charged, saying they needed an opportunity to go before a judge to apply for name suppression.
Mark Inman said he knew his brother would be "hugely disappointed" some of his friends and colleagues could be facing charges.
"At the end of the day, Hayden worked for a professional company and they all did their best to run a very professional, well-regarded and highly-sought adventure tour," he said.
"If anyone had known the eruption was imminent they would not have gone onto the island ... If Hayden was alive he would be very disappointed that charges have been laid.
"People put rules and regulations in place and do their level best to keep people safe but with these types of natural phenomenon tourists are naturally going to be drawn to them.
"It shouldn't be about person blaming but about lesson learnings so that in the event of another natural disaster occurrence the rescue and recovery mission can be done as safely as possible.
"Whether is the Pike River disaster, Mt Erebus or some other tragedy we need to ensure that people learn from it so we try to ensure that it doesn't happen again."
Inman said it was hard to comment further until more details of the WorkSafe prosecution were revealed.
"I understand the legal process has to take its course, including allowing those charged to seek name suppression but I hoped for more transparency over the charges at least."
Inman said criminal charges were not going bring his brother back.
"I have always been adamant no criminal charges should be laid, and that's also the view our family shares."
But the charges have provided "some relief" to Meredith Dallow, whose twin, Gavin Dallow, died with his 15-year-old stepdaughter, Zoe Hosking.
His wife, Lisa, 48 was critically injured, suffering burns to almost 60 per cent of her body.
"I'm not surprised there have been charges laid and I'm actually quite pleased, to be honest," Meredith Dallow said earlier.
"I'm glad the WorkSafe investigation went ahead and there is an outcome but it doesn't really put closure to things," she said from Adelaide.
She believed closure wouldn't come until the court cases and coronial inquest were over.
"It does give us some relief, especially as we come close to the 12-month anniversary."
Steve Milbank, whose son Jake Milbank, 19, will need treatment for the rest of his life after suffering burns to 80 per cent of his body, said news of the charges didn't reveal much.
Milbank said it would be a long time before details of why they were charged would be known and the report's release was only the first stage.
"We're not going to know anything for a while yet."
Earlier Parkes said the charges were the culmination of the most extensive investigation it had ever done.
"This deeply tragic event was unexpected but that does not mean it was unforeseeable."
The 13 parties charged will appear in the Auckland District Court on December 15.
While they haven't been formally named, Prime Minister Jacinda Ardern has confirmed two government agencies, GNS Science and the National Emergency Management Agency are among those charged.
White Island is owned by the Buttle family, through Whakaari Management Limited and its three directors, James, Peter and Andrew Buttle.
Their lawyer also confirmed they had been charged but had yet to receive specific details.