This investigation will run in parallel to a health and safety WorkSafe investigation into the disaster, Police Deputy Commissioner John Tims announced on Tuesday.
WorkSafe would support the police investigation as well as carrying out their own investigation.
As many as 14 people are thought to have been killed by an explosion on the volcanic island on Monday afternoon.
Six people have been confirmed dead, and police were planning the recovery of eight people expected to still be on the island.
The dead include tourists and tour guides, who were among 47 people on the island to view the volcano crater that afternoon.
A spokeswoman for WorkSafe said the investigation would focus on the harm and the loss of life.
WorkSafe New Zealand has opened a health and safety investigation into the harm and loss of life caused by the White Island eruption.
“As the workplace health and safety regulator and administrator of the Adventure Activities Regulations, WorkSafe will be investigating and considering all of the relevant work health and safety issues surrounding this tragic event.”
WorkSafe have made clear that the “waivers” many tour operators used for White Island tours would not remove any legal obligations under the Health and Safety at Work Act.
Employers have to ensure, so far as is reasonably practicable, the health and safety of their workers and other people who could be put at risk by the work of the business. It was not possible to contract out of that requirement.
Workplace Relations Minister Iain Lees-Galloway said matters of compliance “needed to be addressed” but for now the focus would be on victims and their families.
He had received advice from WorkSafe on the matter.
Various warnings were issued in recent weeks about increased activity and gas output at the volcano, with the alert level raised from level one to level two.
Dr. Jessica Johnson, a lecturer of Geophysics at the University of East Anglia, said the eruption was “unfortunate but not completely unexpected”.
“White Island/Whakaari is a very beautiful and interesting destination that naturally attracts tourism. It is very difficult to say whether tourism should be allowed there,” Johnson said.
Dundas Street Employment Lawyers partner Blair Scotland said an employer that was found not to have carried out all its duties could be prosecuted.
If an employer sent employees into a dangerous situation, understanding the risks they were being exposed to, and a death occurred, WorkSafe could look at whether all reasonable practicable steps were taken to address risks, he said.
“It will be interesting to see whether tourism operators or whoever have met their legal obligations in respect to this.”
Bill Hodge, an honorary academic in the faculty of law at the University of Auckland, said tourists would not be able to take personal civil action against tour operators in New Zealand unless they sought punitive damages, claiming the operators had been irresponsible.
Compensation could not be sought for injuries because of the ACC system.