All 13 of the defendants facing charges in relation to the death of 22 people when Whakaari/White Island erupted can now be reported.

The first hearing was today adjourned until June.

Inflite Charters, ID Tours and Tauranga Tourism Services had not previously been reported but today made no application for suppression.

The other 10 parties had already identified themselves.

They are: White Island Tours, Whakaari Management and its directors James, Peter and Andrew Buttle, Kahu NZ, The National Emergency Management Agency, GNS Science, Volcanic Air Safaris and Aerius Ltd.

At today's hearing WorkSafe asked that the matter be adjourned to allow more time for all parties to prepare given the magnitude of the case.

Counsel for White Island Tours, Richard Raymond, also argued that the charges had been filed in the wrong court and should have been filed in Whakatāne rather than Auckland.

The judge agreed to hold the next hearing in Whakatāne and adjourn the matter until June 3.

Arguments into which court the rest of the proceedings would be held in would be heard then.

When WorkSafe chief executive Phil Parkes first announced the charges, he said it concluded the most extensive and complex investigation ever undertaken by WorkSafe.

"We investigated whether those with any involvement in taking tourists to the island were meeting their obligations under the Health and Safety at Work Act 2015.

"We consider that these 13 parties did not meet those obligations. It is now up to the judicial system to determine whether they did or not. WorkSafe can't comment on the matters in front of the court."

This tragedy had a wide-ranging impact on victims, families, communities and iwi, he said.

"There were 47 people on the island at the time of the eruption, all of whom suffered serious injuries and trauma, and 22 of those have lost their lives."

Ten organisations were charged under the Health and Safety at Work Act 2015.

Three individuals were charged under section 44 of the Act which requires directors, or individuals with significant influence over a company, to exercise due diligence that the company is meeting its health and safety obligations.

White Island Tours faced two charges related to alleged offending between April 2017 and December 2019.

Tourists are cleared from White Island following the volcanic eruption December 9, 2019 where 22 were killed. Photo/Michael Schade

Two White Island Tours guides, Jake Milbank and Kelsey Waghorn, were seriously injured in the disaster. Fellow guides Hayden-Marshall Inman and Tipene Maangi lost their lives.

One charge against the company relates to its duty to workers and the other relates to its duty to tourists.

In relation to tourists, the charge particulars allege it was reasonable to: "Ensure booking confirmation, pre-activity information and tour description information provided sufficient detail regarding the hazards and risks, including the risks posed to tourists from volcanic activity, so tourists so could make an informed decision prior to commencing the tour."

Whakaari Management Ltd faces two charges related to alleged offending between April 2016 and December 2019.

The company granted licences to the operators that undertook tours to the volcanic island.

In the particulars of both charges it alleged it was reasonable to ensure that workers and tourists were supplied with "appropriate personal protective equipment".

Whakaari Management Ltd's three directors - James, Peter and Andrew Buttle - each face one charge respectively.

It is alleged that each, as an officer of Whakaari Management Ltd, failed in the duty to exercise due diligence to ensure the company was meeting its health and safety obligations.

Kahu NZ faces two charges related to alleged offending between April 2016 and December 2019.

One charge relates to the health and safety of workers and the other to the health and safety of tourists.

Kahu Helicopters director Mark Law is one of the pilots who helped rescue people from Whakaari after the eruption.

Law rescued five people from the island.

WorkSafe has previously confirmed it did not investigate the rescue and recovery of victims after the eruption. On those matters, no enforcement action has been taken.

The National Emergency Management Agency (formerly Civil Defence and Emergency Management) is also facing a charge for alleged offending between April 2016 and December 2019 at Whakaari/White Island.

The agency provides leadership in reducing risk, being ready for and responding to and recovering from emergencies.

The Institute of Geological and Nuclear Sciences (GNS), Volcanic Air Safaris, and Aerius Ltd face two charges each.

GNS Science monitors volcanic activity in this country, including White Island, and scientists assign an alert level for each volcano.

Inflite Charters Ltd, I D Tours Ltd and Tauranga Tourism Services Ltd also face charges.

For all organisations on each charge the maximum penalty is a fine of $1.5 million.