The final defendant is Whakaari Management, which licenses tours to White Island.

The sentencing date is in February. Fines of up to NZ$1.5m ($928,000; £724,000) could be imposed on the company.

A total of thirteen parties have been charged in connection with the disaster.

Among the others, six pleaded guilty and six had their charges dismissed.

New Zealand’s regulator Worksafe NZ brought the largest case of its kind. The active volcano was “managed and controlled” by Whakaari Management, according to Judge Evangelos Thomas.

A second charge against the company relating to worker safety was also dismissed by the judge.

The company’s owners, James, Andrew, and Peter Buttle, inherited the volcano and licensed other companies to run tours on it.

Since 2011, White Island, also known as Whakaari in Maori, had been erupting in some form.

Volcanic Alert Level 2 was in effect at the time of the disaster on 9 December 2019, which indicated “moderate to heightened volcanic unrest”.