White Island Tours has pleaded guilty to two amended charges, relating to the health and safety regime when Whakaari / White Island erupted in 2019.
A case review hearing was held in Whakatāne District Court on Thursday morning with Judge Evangelos Thomas.
The charges, filed by WorkSafe, relate to having staff and tourists on the island in the lead up to the eruption.
Forty-seven people were on the crater when it erupted on 9 December 2019, with 22 people later dying from extreme burns and blast injuries.
WorkSafe chief executive Phil Parkes is welcoming the guilty pleas.
"The significance of these pleas can't be understated. The survivors and the families of those tourists and workers who died or were seriously harmed will carry this impact for the rest of their lives. They are always at the front of our minds.
"We hope the decision of White Island Tours will provide some assurance to the survivors and family and whānau of those who passed that those who had a duty to ensure their safety and failed to do so are being held to account.
"Those who travelled with White Island Tours and were on Whakaari when it erupted included family groups, couples and friends travelling together. We remember everyone who was impacted by Whakaari," Parkes said.
The company will be sentenced after the trial, which is due to start in July 2023, sitting in Auckland.
GNS Science also pleaded guilty to charges brought against it, earlier this year.
The charges against GNS related to multiple field trips its staff took to the island, before the eruption, and the institute's failure in its duty to the helicopter pilots, who were contractors.
Nine defendants will now go to trial, including island's owners.